Walking device based on planetary roller screw

Abstract

The invention relates to the technical field of robots, in particular to a walking device based on a planetary roller lead screw, and a deformation wheel assembly comprises a standard planetary roller lead screw pair, a hub and the like; the hub comprises a plurality of wheel plates, one end of the connecting supporting rod is fixedly connected with the lead screw, and the other end of the connecting supporting rod is rotationally connected with the center support. The connecting support rod is slidably sleeved with the connecting frame, the connecting frame is fixedly connected with the nut, and the two ends of the first connecting rod are hinged to the connecting frame and the wheel plate respectively; a connecting pin is arranged on the center support, a long groove is formed in one end of each second connecting rod, the connecting pin is in sliding fit with the long groove, and the other end of each second connecting rod is hinged to the corresponding second hinge part. And the first driving motor in the shell is connected with the corresponding lead screw through an electromagnetic clutch. In order to solve the technical problem that an existing walking device has defects, a planetary roller lead screw pair is introduced to serve as a core transmission mechanism, a deformation wheel assembly capable of being switched between a claw shape and a wheel shape is designed on the basis, and the stability and reliability of the walking device are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and particularly relates to a walking device based on a planetary roller screw. Background Art

[0002] In the existing robot technology, the walking device is an important part to satisfy the walking function of the robot. Generally speaking, the walking device is divided into wheel type, leg type or wheel-leg composite type. Different mechanism forms have different characteristics. The existing wheel-leg composite devices generally have the deformation ability, that is, they can freely switch between the wheel type and the leg type through a variable structure, and thus have the advantages of both wheel type devices and leg type devices, so they have attracted much attention.

[0003] However, the existing deformable wheel-leg structures still have some limitations, such as short service life, complex structure, poor deformation ability, and poor stability and reliability after deformation. Therefore, the existing walking devices still need to be improved and developed. Summary of the Invention

[0004] Aiming at the technical problem of the defects existing in the existing walking devices, the present invention provides a walking device based on a planetary roller screw, which introduces a planetary roller screw pair as the core transmission mechanism, and designs a deformable wheel assembly that can switch between a claw shape and a wheel shape on this basis, making full use of the advantages of the planetary roller screw pair, such as large bearing capacity, high precision, long service life, and strong impact resistance, to effectively improve the stability and reliability of the walking device.

[0005] The technical solution provided by the present invention is: a walking device based on a planetary roller screw, comprising a shell and a deformable wheel assembly, wherein the deformable wheel assembly is located on both sides of the shell; the deformable wheel assembly comprises a standard planetary roller screw pair, a connecting frame, a connecting support rod, a central support, a first connecting rod, a second connecting rod and a wheel hub; the wheel hub comprises a plurality of wheel plates, wherein the wheel plates are arc-shaped structures with the same central angle, and the plurality of wheel plates are used to form the circular wheel hub, and a first hinge portion and a second hinge portion are arranged on the wheel plate, and the positions of the first hinge portion and the second hinge portion are symmetrical with the center line L1 of the wheel plate as the symmetry axis; the standard planetary roller screw pair comprises a screw and a nut meshed by rollers, one end of the connecting support rod is fixedly connected to the screw, and the other end of the connecting support rod is rotatably connected to the central support; the connecting frame is slidably sleeved on the outer side of the connecting support rod, The connecting frame is fixedly connected to the nut, and a plurality of rotating connecting seats are provided on the connecting frame, and the two ends of the first connecting rod are respectively hinged with the corresponding rotating connecting seat and the first hinge part; a plurality of connecting pins are provided on the central bracket, and a long groove is provided at one end of the second connecting rod, and the connecting pin is slidably matched with the long groove, and the other end of the second connecting rod is hinged with the corresponding second hinge part; the swinging direction of the first connecting rod is orthogonal to the swinging direction of the second connecting rod; the shell is fixedly provided with a first driving motor with the same number as the deformable wheel assembly, and the output end of the first driving motor is connected to the corresponding lead screw through an electromagnetic clutch; the shell is also provided with at least one second driving motor, and the output end of the second driving motor is fixedly provided with a driving gear, and the outer side of the connecting frame is fixedly provided with a driven gear, and the driving gear is meshed with the driven gear.

[0006] Optionally, the axial length of the driving gear is greater than or equal to the maximum axial movement stroke of the nut.

[0007] Optionally, the second connecting rod has a curvature.

[0008] Optionally, a bearing is provided between the connecting support rod and the central support.

[0009] Optionally, the nut and the connecting frame are connected via a flange.

[0010] Optionally, the lead screw and the connecting rod are connected via a coupling.

[0011] Optionally, a limiting member is provided on a side of the connecting pin facing away from the central support.

[0012] Optionally, a surface of the wheel plate facing away from the central support is provided with a flexible covering or friction texture.

[0013] Adopting the technical solution provided by the present invention, compared with the prior art, it has the following beneficial effects: Aiming at the technical problem that the existing walking device has defects, the walking device based on the planetary roller screw provided by the present invention introduces a planetary roller screw pair as the core transmission mechanism, and on this basis, a deformable wheel assembly that can be switched between a claw shape and a wheel shape is designed, making full use of the advantages of the planetary roller screw pair such as large bearing capacity, high precision, long service life, and strong impact resistance, effectively improving the stability and reliability of the walking device. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. is a schematic structural diagram of a walking device based on a planetary roller screw proposed in an embodiment of the present invention.

[0015] Figure 2 FIG. is one of the schematic structural diagrams of the deformable wheel assembly proposed in an embodiment of the present invention.

[0016] Figure 3 FIG. is another schematic structural diagram of the deformable wheel assembly proposed in an embodiment of the present invention.

[0017] Figure 4 FIG. is a third schematic structural diagram of the deformable wheel assembly proposed in an embodiment of the present invention.

[0018] Figure 5 FIG. is a schematic structural diagram of the connecting frame proposed in an embodiment of the present invention.

[0019] Figure 6 FIG. is a schematic structural diagram of the wheel plate proposed in an embodiment of the present invention.

[0020] Figure 7 FIG. is an assembly schematic diagram of the electromagnetic clutch proposed in an embodiment of the present invention.

[0021] Figure 8 FIG. is a schematic structural diagram of a standard planetary roller screw pair proposed in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] To further understand the content of the present invention, the present invention will be described in detail in combination with the drawings and embodiments.

[0023] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related invention, rather than limiting the invention. Additionally, it should be noted that for the sake of convenience in description, only the parts related to the invention are shown in the drawings. The terms "first", "second", etc. used in the present invention are set for the convenience of describing the technical solution of the present invention and have no specific limiting effect. They are all general references and do not constitute a limiting effect on the technical solution of the present invention. It should be noted that, without conflict, the embodiments and features in the embodiments of the present application can be combined with each other. In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Unless otherwise clearly defined and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Multiple technical solutions in the same embodiment, as well as multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions without contradiction or conflict, and all are within the scope of protection required by the present invention.

[0024] In combination with the attached Figure 1-8 , this embodiment proposes a walking device based on a planetary roller screw, including a housing 1 and a deformable wheel assembly. The deformable wheel assembly is located on both sides of the housing 1, and two deformable wheel assemblies are provided in this embodiment.

[0025] Among them, the deformable wheel assembly includes a standard planetary roller screw pair 2, a connecting frame 3, a connecting support rod 4, a central support 5, a first connecting rod 6, a second connecting rod 7, and a hub. The hub includes a plurality of wheel plates 8. The wheel plates 8 are arc-shaped structures with the same central angle, and the plurality of wheel plates 8 are used to form a circular hub.

[0026] The first hinge portion 801 and the second hinge portion 802 are provided on the wheel plate 8, and the positions of the first hinge portion 801 and the second hinge portion 802 are symmetric about the center line L1 of the wheel plate 8. In this embodiment, the hub includes three wheel plates 8, and the central angle corresponding to the contour of each wheel plate 8 is 120°.

[0027] The standard planetary roller screw pair 2 includes a screw 201 and a nut 202 meshed through rollers 203. The nut 202 is sleeved outside the screw 201, and the rollers 203 are located between the nut 202 and the screw 201. The rollers 203 are threadedly meshed with the nut 202 and the screw 201 respectively. The standard planetary roller screw pair 2 serves as the core transmission mechanism of the deformable wheel assembly. This transmission mechanism is a new type of rolling screw mechanism that can mutually convert the rotational motion of the screw 201 and the linear reciprocating motion of the nut 202. It mainly transmits power through the threaded meshing between the rollers 203, the screw 201, and the nut 202, and has the advantages of large bearing capacity, high precision, long service life, and strong impact resistance.

[0028] One end of the connecting rod 4 is fixedly connected to the screw 201, and the other end of the connecting rod 4 is rotatably connected to the central bracket 5; the connecting frame 3 is slidably sleeved outside the connecting rod 4, the connecting frame 3 is fixedly connected to the nut 202, and a number of rotating connection seats 301 are arranged on the connecting frame 3. Both ends of the first connecting rod 6 are respectively hinged to the corresponding rotating connection seat 301 and the first hinge portion 801.

[0029] A number of connecting pins 501 are arranged on the central bracket 5. One end of the second connecting rod 7 is provided with a long slot 701, and the connecting pin 501 is slidably matched with the long slot 701. The other end of the second connecting rod 7 is hinged to the corresponding second hinge portion 802; the swinging direction of the first connecting rod 6 is orthogonal to the swinging direction of the second connecting rod 7.

[0030] A first driving motor 9 with the same quantity as the deformable wheel assembly is fixedly arranged in the housing 1. The output end of the first driving motor 9 is connected to the corresponding screw 201 through an electromagnetic clutch 10; at least one second driving motor is also arranged in the housing 1. The output end of the second driving motor is fixedly provided with a driving gear 11, and a driven gear 12 is fixedly arranged outside the connecting frame 3. The driving gear 11 is meshed and matched with the driven gear 12.

[0031] The walking device based on the planetary roller screw in this embodiment can be used as a robot mobile platform and applied to different scenarios. The deformable wheel assembly therein can realize the free transformation between the claw shape and the wheel shape (i.e., circular shape) through the driving transmission of the standard planetary roller screw pair 2.

[0032] Overall, the working principle of the walking device based on the planetary roller screw in this embodiment is as follows: When the walking device needs to walk, the shape of the deformable wheel assembly is determined and unchanged. The second driving motor drives the connecting frame 3, the central bracket 5, the first connecting rod 6, the second connecting rod 7, and the hub to rotate circumferentially through the meshing of the driving gear 11 and the driven gear 12, and the wheel plate 8 on the hub contacts the ground, thereby realizing the walking motion.

[0033] The output end of the first driving motor 9 is connected to the corresponding lead screw 201 through an electromagnetic clutch 10. When the above-mentioned walking process occurs, the electromagnetic clutch 10 is in the off state, that is, the driven gear 12 will drive the whole standard planetary roller screw pair 2 to rotate together, but will not cause the first driving motor 9 to rotate synchronously, ensuring the normal operation of the deformable wheel assembly.

[0034] When the walking device encounters an obstacle during the walking process and the deformable wheel assembly needs to deform, the second driving motor stops working. After the walking device stops walking, the electromagnetic clutch 10 is turned on, and the first driving motor 9 works. At this time, the deformable wheel assembly can complete the switching deformation process between the claw shape and the wheel shape.

[0035] After the deformation is completed, the electromagnetic clutch 10 is disconnected, and the second driving motor also stops working. The first driving motor 9 restarts, and the hub of the deformable wheel assembly after deformation can then perform circular motion again, thus realizing the walking function.

[0036] Among them, the electromagnetic clutch 10 can be selected as the DDL3 series single-disc electromagnetic clutch 10 of Tianjin Machine Tool Electric Co., Ltd., or other similar electromagnetic clutches 10. Taking the common single-disc electromagnetic clutch 10 as an example, the rotor part of the electromagnetic clutch 10 is fixedly connected to the output end of the first driving motor 9, and the friction plate part is fixedly connected to the lead screw 201. When the rotor part is powered on, a magnetic field can be generated to adsorb the armature fixed to the friction plate part. When it is engaged, it is the on state of the electromagnetic clutch 10. At this time, the output end of the first driving motor 9 can rotate synchronously with the lead screw 201. When it is not engaged, the electromagnetic clutch 10 is in the off state, and the output end of the first driving motor 9 will not rotate synchronously with the lead screw 201.

[0037] In a preferred embodiment, the axial length of the driving gear 11 should be greater than or equal to the maximum axial movement stroke of the nut 202 in the standard planetary roller screw pair 2, so as to ensure that the second driving motor can drive the hub to achieve circumferential rotation in any deformation state of the deformable wheel assembly.

[0038] Further, for the transformation between the claw shape and the wheel shape of the deformable wheel assembly, its working principle is as follows: In the initial state, the hub in the deformable wheel assembly is in a complete circular shape, that is, at this time, when the wheel plates 8 are connected end to end in sequence along the circumferential direction, a complete wheel shape is formed. When it is necessary to transform from the wheel shape to the claw shape, the lead screw 201 in the standard planetary roller screw pair 2 is driven by the first driving motor 9, and the nut 202 thereon moves linearly along the axial direction, pushing the connecting frame 3 to slide axially relative to the connecting support rod 4. During the axial sliding of the connecting frame 3, the first connecting rod 6 applies a thrust to one side of the wheel plate 8, causing the side where the first hinge portion 801 of the wheel plate 8 is located to open outward. Correspondingly, the second connecting rod 7 connected to the second hinge portion 802 of the wheel plate 8 will perform a combined movement of swinging and translation, and the hub is thus deformed into a claw shape.

[0039] Based on the above principle, it can be known that the deformable wheel assembly of this embodiment can adjust the deformation degree of the wheel plate 8 by changing the axial movement stroke of the nut 202 on the standard planetary roller screw pair 2.

[0040] Moreover, when the hub needs to be transformed from the claw shape to the circular shape, the first driving motor 9 starts in the reverse direction, driving the lead screw 201 to reverse, and the nut 202, the connecting frame 3, etc. all move in the opposite way to realize the reset of the wheel plate 8, and finally deform into a circular hub.

[0041] In the deformable wheel assembly of this embodiment, during the process of the wheel shape being transformed into the claw shape, when the wheel plate 8 opens, it will cause a relative movement of compound translation and rotation between the second connecting rod 7 and the pin. Therefore, a long slot 701 is provided at one end of the second connecting rod 7, and the connecting pin 501 on the central support 5 is in sliding fit with the long slot 701 to adapt to this compound movement.

[0042] Since the connecting pin 501 and the long slot 701 are in cooperation, when the hub forms a circular shape, there will also be a certain degree of relative sliding between the long slot 701 on the wheel plate 8 (generally referring to the wheel plate 8 in contact with the ground) under pressure and the corresponding second connecting rod 7, resulting in a certain degree of deformation of the hub from a circular wheel to a claw-shaped wheel at this wheel plate 8. Due to the small amount of deformation, this deformation can still possess the functionality of a circular wheel to a great extent. At the same time, this slight deformation tending to the claw shape can endow the hub with better grip ability.

[0043] This deformation can improve the adaptability of the deformable wheel assembly to the terrain and expand the passing ability of the circular hub. Therefore, this form of cooperation between the connecting pin 501 and the long slot 701 further enables the deformable wheel assembly of this embodiment to have an adaptive adjustment characteristic to further meet the grip requirements during obstacle crossing.

[0044] In addition, since the wheel hub needs to bear the load and the mating form of the connecting pin 501 and the long slot 701 may become loose, in a preferred embodiment, a limiting member may be provided on the side of the connecting pin 501 facing away from the central bracket 5. Generally speaking, the limiting member can be a plug pin, or a limiting boss, a baffle or a nut, etc. can be provided at the end of the pin facing away from the central bracket 5 to prevent the connecting pin 501 from slipping out of the long slot 701.

[0045] In this embodiment, the standard planetary roller screw pair 2 can provide self-locking ability through its own mechanism, ensuring the rigidity of the wheel hub in any form, so that the wheel hub will not easily deform when subjected to external forces. In addition, the swinging direction of the first connecting rod 6 is orthogonal to the swinging direction of the second connecting rod 7, which further enables the wheel hub to have self-locking characteristics, further ensuring the rigidity of each wheel plate 8 after deformation, and thus ensuring that the deformable wheel assembly has excellent load-bearing capacity.

[0046] It should be noted that in this embodiment, the first hinge portion 801 and the second hinge portion 802 are only symmetric about the center line L1 of the wheel plate 8 at their respective positions, but the directions of their respective hinge connections are different.

[0047] In other embodiments, the second connecting rod 7 has a radian, and the design of the radian enables the wheel plate 8 to have a larger opening radian compared with a straight rod in the same space, and the wheel hub can have a larger claw-shaped deformation. In other words, the second connecting rod 7 with a radian can further save space.

[0048] Combined with the above principle description, the connecting frame 3 is slidably sleeved outside the connecting support rod 4, and one end of the connecting support rod 4 is fixedly connected to the lead screw 201. To ensure that the deformable wheel assembly can deform, one end of the connecting support rod 4 must be rotatably connected to the central bracket 5, so as to rely on the friction between the ground and the wheel plate 8 to ensure that the central bracket 5 does not rotate together with the lead screw 201 and the connecting support rod 4. To make the relative rotation between the connecting support rod 4 and the central bracket 5 smoother, in a preferred embodiment, a bearing is provided between the connecting support rod 4 and the central bracket 5.

[0049] In a preferred embodiment, the nut 202 and the connecting frame 3 are connected by a flange. Specifically, flange plates can be provided on the nut 202 and the connecting frame 3 to achieve flange connection. In addition, the lead screw 201 and the connecting support rod 4 are preferably connected by a coupling to ensure the transmission effect.

[0050] To reduce the direct wear of the wheel hub and enable it to have the ability to pass through rough terrains, a flexible covering can be provided on the side of the wheel plate 8 facing away from the central bracket 5. The flexible covering can be a rubber tread or rubber ribs arranged in a specific pattern, etc.

[0051] Furthermore, friction patterns may be provided on the surface of the wheel plate 8 so that the wheel plate 8 has greater friction, thereby improving the practicality of the wheel hub.

[0052] In short, the walking device of this embodiment has high flexibility and good obstacle crossing ability. It can travel on different terrains by changing the deformation amplitude of the wheel hub. It can travel on flat roads like common round wheels, or it can be converted into claw-shaped wheels to travel on rugged roads or on roads with stairs. The walking device is easy to manufacture and maintain, and has strong rigidity, so it can cope with complex environments.

[0053] Moreover, the walking device of this embodiment introduces a standard planetary roller screw pair 2 as the core transmission mechanism, and designs a deformable wheel assembly that can switch between claw shape and wheel shape based on this, making full use of the advantages of the standard planetary roller screw pair 2 such as large load-bearing capacity, high precision, long life, and strong impact resistance, thereby effectively improving the stability and reliability of the walking device.

[0054] The present invention and its embodiments are described schematically above, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and creatively designs a structure and an embodiment similar to the technical solution without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A walking device based on a planetary roller screw, characterized in that: It comprises a housing (1) and a deformation wheel assembly, wherein the deformation wheel assembly is located on both sides of the housing (1); The deformable wheel assembly comprises a standard planetary roller screw pair (2), a connecting frame (3), a connecting support rod (4), a central support (5), a first connecting rod (6), a second connecting rod (7) and a wheel hub; The wheel hub comprises a plurality of wheel plates (8), each of which is an arc-shaped structure having the same central angle, and the plurality of wheel plates (8) are used to form the circular wheel hub, and a first hinge portion (801) and a second hinge portion (802) are provided on the wheel plate (8), and the positions of the first hinge portion (801) and the second hinge portion (802) are symmetrical with the center line L1 of the wheel plate (8) as the symmetry axis; The standard planetary roller screw pair (2) comprises a screw (201) and a nut (202) meshed by a roller (203); one end of the connecting rod (4) is fixedly connected to the screw (201), and the other end of the connecting rod (4) is rotatably connected to the central support (5); the connecting frame (3) is slidably sleeved on the outer side of the connecting rod (4), the connecting frame (3) is fixedly connected to the nut (202), and a plurality of rotating connecting seats (301) are provided on the connecting frame (3); the two ends of the first connecting rod (6) are respectively hinged to the corresponding rotating connecting seats (301) and the first hinged portion (801); The central support (5) is provided with a plurality of connecting pins (501); one end of the second connecting rod (7) is provided with a long slot (701); the connecting pin (501) is slidably matched with the long slot (701); the other end of the second connecting rod (7) is hinged to the corresponding second hinged portion (802); the swinging direction of the first connecting rod (6) is orthogonal to the swinging direction of the second connecting rod (7); The housing (1) is fixedly provided with a number of first drive motors (9) which is the same as the number of the deformable wheel assemblies, and the output end of the first drive motor (9) is connected to the corresponding lead screw (201) via an electromagnetic clutch (10); the housing (1) is also provided with at least one second drive motor, and the output end of the second drive motor is fixedly provided with a driving gear (11), and the outer side of the connecting frame (3) is fixedly provided with a driven gear (12), and the driving gear (11) is meshed with the driven gear (12).

2. A walking device based on a planetary roller screw according to claim 1, characterized in that: The axial length of the driving gear (11) is greater than or equal to the maximum axial movement stroke of the nut (202).

3. A walking device based on a planetary roller screw according to claim 1, characterized in that: The second connecting rod (7) has a curvature.

4. A walking device based on a planetary roller screw according to claim 1, characterized in that: A bearing is provided between the connecting rod (4) and the central support (5).

5. A walking device based on a planetary roller screw according to claim 1, characterized in that: The nut (202) and the connecting frame (3) are connected via a flange.

6. A walking device based on a planetary roller screw according to claim 1, characterized in that: The lead screw (201) and the connecting support rod (4) are connected via a coupling.

7. A walking device based on a planetary roller screw according to claim 1, characterized in that: A limiting member is provided on the side of the connecting pin (501) facing away from the central support (5).

8. A walking device based on a planetary roller screw according to claim 1, characterized in that: A flexible covering or friction pattern is provided on the surface of the wheel plate (8) facing away from the central support (5).

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