Flexible mechanical arm limiting lock catch structure based on rope-driven variable stiffness, flexible mechanical arm and unmanned aerial vehicle

Abstract

The invention relates to a flexible mechanical arm limiting lock catch structure based on rope-driven variable rigidity, a flexible mechanical arm and an unmanned aerial vehicle. The structure comprises a rope driving assembly, a limiting lock catch assembly and a friction locking assembly. The limiting lock catch assembly comprises a plurality of rigid unit pieces connected in series, the adjacent rigid unit pieces are rotationally connected, the rope driving assembly comprises a motor and a rope, the rope penetrates through the rigid unit pieces, one end of the rope is connected with the motor, and the other end of the rope is connected with the rigid unit piece at the tail end of the limiting lock catch assembly. The friction locking assemblies are elastic interlayers, the elastic interlayers are arranged between the adjacent rigid unit pieces, and when the rope is tensioned, friction damping is provided for the rigid unit pieces. Compared with the prior art, the invention has the advantages of simple driving, convenient rigid-flexible switching, strong environmental adaptability and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of mechanical arm structure, and particularly to a flexible mechanical arm limiting lock structure based on variable stiffness of rope driving, a flexible mechanical arm and a UAV. BACKGROUND

[0002] With the continuous evolution of robot technology, flexible mechanical arms have good environmental adaptability, and their application demand in various fields such as industrial manufacturing, medical rehabilitation and disaster rescue continues to rise, and they have become one of the research hotspots in the field of robots. The core design goal of the flexible mechanical arm is to realize flexible operation and safe interaction in complex environments, and its technical development process has always revolved around the optimization of motion control accuracy, structural flexibility, system lightness and dynamic response performance.

[0003] In the existing technical system, the motion control of the flexible mechanical arm mainly depends on the combination structure of rigid connecting rods and motor driving. This kind of structure draws lessons from the design idea of traditional industrial robots, and realizes posture adjustment and work execution through the series connection of rigid linkers and the precise driving of motors, which shows high motion accuracy advantage in repetitive operation scenes of structured factories. However, when facing complex unstructured environments such as climbing trees, pipe detection and barrier stopping, its inherent defects become more prominent: on the one hand, the structural characteristics of rigid connecting rods lead to insufficient overall flexibility, making it difficult to adapt to irregular curved surfaces for adaptive gripping; on the other hand, the integration of motor driving system makes the overall weight of the mechanical arm heavier and the motion inertia higher, which not only limits its application in lightweight operation scenes, but also leads to slow dynamic response, and cannot quickly respond to the posture adjustment demand brought by environmental changes.

[0004] In order to break through the limitations of traditional structures, improved flexible mechanical arm structures that introduce variable stiffness control strategies have been gradually developed in the industry, which adjust the joint stiffness through motor, hydraulic or pneumatic driving methods, trying to realize the operation performance of rigid and flexible combination. For example, some schemes adjust the stiffness by changing the tension of the motor-driven tendon, some schemes realize the flexible adjustment of the joint by means of the pressure control of the hydraulic circuit, and some researches use pneumatic driving mechanical metamaterial structure to change the overall stiffness by switching between vacuum and inflation states.

[0005] Although such improved schemes improve environmental adaptability to some extent, there are still many technical bottlenecks: the system needs to be additionally equipped with a complex transmission mechanism and a power source, resulting in redundant system structure, significant increase in overall weight and energy consumption, and difficulty in meeting the portable operation demand; even if the pneumatic driving scheme is adopted, the traditional design has the problem of limited stiffness adjustment speed, and most of the system response time is in the order of hundreds of milliseconds, which cannot realize real-time interaction and rapid stiffness switching in a dynamic environment, and it is difficult to meet the changing operation demand in disaster rescue and other scenes. In addition, the control logic of the existing variable stiffness system depends on the real-time calculation of software algorithms, which has the risk of response delay, and fails to fully utilize the physical intelligent characteristics of the mechanical structure itself, further limiting the improvement of its dynamic performance.

[0006] In recent years, the application scenarios of robots have gradually expanded from closed structured factories to open unstructured environments, and emerging scenarios such as disaster rescue, field exploration and human-robot co-integration care have put forward higher requirements for flexible manipulators. In the disaster rescue scenario, the robot needs to flexibly shuttle in the collapsed building ruins to realize the positioning and material delivery of trapped personnel, and the manipulator needs to have the ability of lightweight, high flexibility and rapid stiffness adjustment; in the field exploration scenario, the manipulator needs to realize safe parking and accurate operation on irregular carriers such as branches and rocks, which puts forward strict challenges to its self-adaptive gripping performance and dynamic response speed; and in the human-robot co-integration operation scenario, the manipulator needs to have collision safety buffer capability while ensuring operation accuracy, so as to avoid causing harm to the human body. The flexible manipulator with variable stiffness capability has irreplaceable advantages in the above scenarios, and becomes a core key component to promote the practicalization and landing of robot technology.

[0007] In summary, the existing flexible manipulator, whether it is a traditional rigid connecting rod and motor-driven structure or an improved variable stiffness control structure, cannot fully meet the comprehensive demand for flexibility, lightweight, rapid response and safe interaction in complex unstructured environments. Therefore, developing a flexible manipulator structure that is efficient, lightweight and has rapid response capability, breaking through the technical bottlenecks of the existing technology, has important research value and wide application prospect for expanding the application boundary of robots and improving the operation capability in extreme environments. SUMMARY

[0008] The purpose of the present application is to overcome the defects of the prior art, such as complex driving, difficult rigid-flexible switching and insufficient environmental adaptability in the structure of the existing flexible manipulator, and to provide a flexible manipulator limit lock structure based on rope-driven variable stiffness, a flexible manipulator and a unmanned aerial vehicle.

[0009] The purpose of the present application can be achieved by the following technical solutions: The scheme provides a flexible mechanical arm limiting lock structure based on rope driving variable rigidity, which comprises a rope driving assembly, a limiting lock assembly and a friction locking assembly; the limiting lock assembly comprises a plurality of serially connected rigid unit pieces, adjacent rigid unit pieces are rotatably connected, the rope driving assembly comprises a motor and a rope, the rope penetrates through each rigid unit piece, and one end of the rope is connected with the motor, and the other end is connected with a rigid unit piece at the end of the limiting lock assembly; the friction locking assembly is an elastic interlayer, and the elastic interlayer is arranged between adjacent rigid unit pieces, and provides friction damping for the rigid unit piece when the rope is tensioned.

[0010] Preferably, the rigid unit piece comprises a rotating part and a limiting part. The rotating part is in a ring structure, the limiting part is in an arc structure, the rotating part is fixed at one end of the limiting part away from the opening, and the central axis of the rotating part is parallel to the central axis of the limiting part.

[0011] Preferably, the opening width of the limiting part is greater than the diameter of the rotating part, and the limiting part is provided with a clamping groove matched with the rotating part, and the rotating part is rotatably installed in the clamping groove.

[0012] Preferably, the elastic interlayer is fixed in the clamping groove through the adhesive.

[0013] Preferably, the rotating part and the limiting part are integrally formed, one end of the rotating part away from the limiting part is provided with an arc swing groove, and the connecting part of the rotating part and the limiting part is provided with a through hole matched with the rope.

[0014] Preferably, the central angle range of the arc swing groove corresponds to 90-120 degrees.

[0015] Preferably, the elastic interlayer is a clamping layer structure of a first polytetrafluoroethylene layer, a silica gel layer and a second polytetrafluoroethylene layer stacked in sequence.

[0016] Preferably, the rope driving assembly further comprises a rigid motor shell, the motor is installed in the rigid motor shell, and one end of the limiting lock assembly is fixed at the bottom in the rigid motor shell.

[0017] The scheme also provides a flexible mechanical arm, which at least comprises the flexible mechanical arm limiting lock structure based on rope driving variable rigidity.

[0018] The scheme also provides an unmanned aerial vehicle, which comprises an unmanned aerial vehicle body, and further comprises the flexible mechanical arm.

[0019] Compared with the prior art, the present application has the following advantages: (1) The scheme replaces the complex electric joint structure with a rope driving system, so that the device has simple structure, light weight and fast response speed. The elastic interlayer arranged between the rigid unit pieces can buffer the impact between the rigid unit pieces when the rope is loosened, adapt to irregular surfaces, provide frictional damping when the rope is tensioned, and realize the locking of the rigid unit pieces. The elastic interlayer can ensure the stability of the connection of the rigid unit pieces and the safety of the component, and realize the quick and smooth switching between the flexible and rigid states. In the flexible state, the mechanical arm can be naturally hung, swung and wound, and in the rigid state, the target can be stably locked, and the switching process is efficient and fast.

[0020] (2) In the scheme, the rigidity adjustment of the limiting lock assembly is realized by the rope transmission mode cooperating with the friction locking of the elastic interlayer, a large friction force is generated between the rigid unit pieces, the relative rotation of the rigid unit pieces is limited, overload damping protection is provided, and the safety and service life of the flexible mechanical arm are significantly improved.

[0021] (3) The limiting lock assembly structure of the flexible mechanical arm in the scheme is simple, the rigid unit pieces are connected in series by the rope, and the corresponding elastic interlayer is arranged between the adjacent rigid unit pieces, without complex transmission adjustment structure, so that the overall structure is simple, the assembly is convenient, and the maintenance cost is low. It can be flexibly used in scenes such as climbing robots, flexible mechanical arms and unmanned aerial vehicles that need to change structures, and has flexible use and wide application range. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The structure schematic diagram of the flexible mechanical arm limiting lock structure in a hanging state is provided. Figure 2 The structure schematic diagram of the structure carried on the unmanned aerial vehicle platform is provided. Figure 3 The connection structure section view of the rigid unit piece and the elastic interlayer is provided. In the figure: 1, rigid unit piece, 2, elastic interlayer, 3, rope, 4, rigid motor shell, 5, motor, 11, rotating part, 12, limiting part, 13, arc swing groove, 14, through hole. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] The following detailed description of embodiments of the application in the drawings provided is not intended to limit the scope of the application claimed, but merely represents selected embodiments of the application. Based on the embodiments of the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.

[0025] It should be noted that similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0026] In the description of the application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the application is usually placed, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0027] It should be noted that the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0028] In addition, the terms "horizontal", "vertical" and the like do not mean that the parts must be absolutely horizontal or vertical, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0029] Embodiment 1 As shown in Figure 1 and Figure 2 The present embodiment provides a flexible robot arm limiting lock structure based on rope driving variable stiffness, which comprises a rope driving assembly, a limiting lock assembly and a friction locking assembly. The limiting lock assembly comprises a plurality of rigid unit pieces 1 connected in series, and the adjacent rigid unit pieces 1 are rotatably connected. The rope driving assembly comprises a motor 5 and a rope 3, the rope 3 penetrates through each rigid unit piece 1, and one end of the rope 3 is connected to the motor 5, and the other end is connected to the rigid unit piece 1 at the end of the limiting lock assembly. The friction locking assembly is an elastic interlayer 2, and the elastic interlayer 2 is arranged between adjacent rigid unit pieces 1, and provides friction damping for the rigid unit piece 1 when the rope 3 is tensioned.

[0030] Working principle: When rope 3 is tightened, adjacent rigid unit plates 1 compress the elastic interlayer 2, generating significant friction on the rigid unit plates 1. This restricts relative rotation between the rigid unit plates 1, locking the limit locking assembly and placing it in a rigid state. Conversely, when rope 3 is loosened, friction decreases, allowing the rigid unit plates 1 to rotate freely, and the limit locking assembly becomes flexible, thus achieving variable stiffness adjustment of the robotic arm.

[0031] By utilizing a rope-driven system to replace the complex motor joint structure, the device achieves a simple structure, light weight, and fast response. An elastic interlayer between the rigid unit pieces buffers the impact between the rigid unit pieces and adapts to irregular surfaces when the rope is released, while providing frictional damping when the rope is tensioned, thus locking the rigid unit piece 1. The elastic interlayer ensures the stability of the rigid unit piece connection and the safety of the components, while enabling rapid and smooth switching between flexible and rigid states. In the flexible state, the robotic arm can naturally hang, swing, and wrap around; in the rigid state, it can firmly lock the target. The switching process is efficient and responsive.

[0032] Preferred implementation methods, such as Figure 3 As shown, the rigid unit piece 1 includes a rotating part 11 and a limiting part 12; the rotating part 11 has a ring structure and the limiting part 12 has an arc structure. The rotating part 11 is fixed at the end of the limiting part 12 away from the opening, and the central axis of the rotating part 11 is parallel to the central axis of the limiting part 12.

[0033] In this embodiment, the opening width of the limiting part 12 is greater than the diameter of the rotating part 11, and the limiting part 12 is provided with a slot that cooperates with the rotating part 11, so that the rotating part 11 can be rotatably installed in the slot. The elastic interlayer 2 is fixed in the slot by adhesive backing.

[0034] Specifically, the rotating part 11 of the rigid unit piece 1 is installed into the slot of the limiting part of other rigid unit pieces, and the rigid unit pieces 1 are connected in series. The rotating part 11 can rotate in the slot. The central angle corresponding to the opening of the limiting part has a limiting effect on the rotation range of the next rotating part 11, thereby ensuring the structural reliability and safety.

[0035] In this embodiment, the rotating part 11 and the limiting part 12 are integrally formed, and the end of the rotating part 11 away from the limiting part 12 is provided with an arc-shaped swing groove 13; the connection between the rotating part 11 and the limiting part 12 is provided with a through hole 14 that cooperates with the rope 3. The central angle corresponding to the arc-shaped swing groove 13 is 90 degrees.

[0036] The rope 3 can be a steel wire rope, which passes through the arc swing groove 13 and the through hole 14, and the end is fixed on the last rigid unit piece, so as to connect and fix the rigid unit pieces in series. The arc swing groove 13 on the rotating part 11 can avoid the influence of the rope tensioning on the rotating range of the rigid unit piece, and the through hole 14 can ensure the stability of the connection between the rigid unit pieces, and the structure is simple and reasonable.

[0037] In the embodiment, the elastic interlayer 2 is a sandwich structure of a first polytetrafluoroethylene layer, a silica gel layer and a second polytetrafluoroethylene layer stacked in sequence. Overload damping protection is provided, and the system safety and service life are significantly improved In the embodiment, the rope driving assembly further comprises a rigid motor shell 4, and the motor 5 is installed in the rigid motor shell 4. One end of the limit lock assembly is fixed to the bottom in the rigid motor shell 4.

[0038] The embodiment also provides a flexible mechanical arm limit lock structure based on a rope driving variable stiffness control, which comprises a rope driving system, a limit lock assembly and a friction locking assembly. The limit lock assembly is composed of a plurality of rigid unit pieces 1, and adjacent rigid unit pieces 1 are connected through a PTFE-silica gel-PTFE interlayer 2 to form a multi-degree-of-freedom structure with rotating ability. The rope driving system is composed of a motor, a rigid motor shell 4 and a steel wire rope 3. The motor is installed in the rigid motor shell 4, and the output shaft is connected with the steel wire rope 3. The tension of the overall structure is adjusted by tightening or loosening the rope. The friction locking assembly is composed of a PTFE-silica gel-PTFE interlayer 2 and its adhesive fixing structure. The interlayer is used for buffering and reducing impact, adapting to irregular surfaces, and providing friction damping when the rope is tensioned.

[0039] In the embodiment, the rope driving system is composed of a micro reduction motor, a rigid motor shell 4, a steel wire rope and a motor control module. The micro reduction motor is fixedly installed in the rigid motor shell 4, and precise driving control is realized through the motor control module. The output end of the module is connected with the micro reduction motor, the forward and reverse rotation and the rotating speed of the motor output shaft are controlled, so that the steel wire rope is tightened or loosened to realize precise control of the rope tension. When the micro reduction motor tightens the steel wire rope, the rope tension increases, so that the limit lock assemblies in the mechanism are linked; when the micro reduction motor loosens the steel wire rope, the rope tension decreases, and the mechanism returns to the natural suspended state, realizing the conversion between the flexible and rigid states.

[0040] In the embodiment, the limit lock assembly is composed of a plurality of rigid unit pieces 1, and any adjacent rigid unit pieces 1 are connected through a PTFE-silica gel-PTFE interlayer 2. The flexibility and friction performance of the interlayer can realize the constraint and release of joint rotation. The rigid unit pieces 1 can be connected in series or installed in sections according to the length requirement of the mechanical arm, so as to meet the configuration requirement of different flexible mechanical arms.

[0041] When the steel wire rope 3 is tightened, the adjacent rigid unit pieces 1 generate a large friction force through the PTFE-silica gel-PTFE sandwich 2, limiting their relative rotation, and the structure enters a rigid state; when the steel wire rope 3 is loosened, the friction force decreases, the rigid unit pieces 1 can freely rotate between them, and the mechanism is in a flexible state, thereby realizing the rigid-flexible integrated variable stiffness adjustment of the mechanical arm.

[0042] In this embodiment, the friction locking assembly includes a PTFE-silica gel-PTFE sandwich 2 and its self-adhesive fixing structure, and the PTFE-silica gel-PTFE sandwich 2 is installed on the contact surface between the rigid unit pieces 1. The silica gel has a high friction coefficient, and different thicknesses or hardnesses of silica gel materials can be selected according to actual needs to control the locking friction force.

[0043] When the steel wire rope 3 is tightened by the micro speed reducer motor 5, the contact pressure between the rigid unit pieces 1 increases, the PTFE-silica gel-PTFE sandwich 2 generates a large friction force, and the structure is locked; when the micro speed reducer motor 5 is reversed to loosen the steel wire rope 3, the friction force decreases, and the mechanism returns to a flexible state, thereby realizing reversible rigid-flexible switching.

[0044] The embodiment also provides a flexible mechanical arm, which at least includes the above-mentioned flexible mechanical arm limiting lock catch structure based on rope-driven variable stiffness. The stiffness of the limiting lock catch assembly can be continuously adjusted through the rope, so that the flexible mechanical arm adapts to the stiffness requirements of different working scenes. Moreover, the limiting lock catch structure is small in size and can be directly fixed at the joint of the flexible mechanical arm, without affecting the overall flexibility of the flexible mechanical arm.

[0045] The embodiment also provides an unmanned aerial vehicle, which includes an unmanned aerial vehicle body, and further includes the above-mentioned flexible mechanical arm, which is installed on the unmanned aerial vehicle body. The flexible mechanical arm is easy to assemble and has low maintenance cost, and can be widely applied to scenarios such as climbing robots, flexible mechanical arms, and unmanned aerial vehicle variable structure systems. Remote collaborative control is realized through wireless communication, and only the rotation of the motor is needed to realize the stiffness adjustment of the flexible mechanical arm, which is convenient to operate and improves the operation safety and efficiency without close human operation.

[0046] The above describes the preferred embodiments of the present application in detail. It should be understood that those skilled in the art can make many modifications and changes without creative labor based on the concept of the present application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment based on the prior art according to the concept of the present application shall be within the protection scope defined by the claims.

Claims

1. A limit locking structure for a flexible robotic arm based on rope-driven variable stiffness, characterized in that, The system includes a rope drive assembly, a limit lock assembly, and a friction locking assembly. The limit lock assembly includes multiple rigid unit pieces (1) connected in series, with adjacent rigid unit pieces (1) rotatably connected. The rope drive assembly includes a motor (5) and a rope (3). The rope (3) passes through each rigid unit piece (1), and one end of the rope (3) is connected to the motor (5), while the other end is connected to the rigid unit piece (1) at the end of the limit lock assembly. The friction locking assembly is an elastic interlayer (2), with an elastic interlayer (2) provided between adjacent rigid unit pieces (1) to provide frictional damping for the rigid unit pieces (1) when the rope (3) is tensioned.

2. The flexible robotic arm limiting lock structure based on rope-driven variable stiffness according to claim 1, characterized in that, The rigid unit piece (1) includes a rotating part (11) and a limiting part (12). The rotating part (11) has a ring structure, the limiting part (12) has an arc structure, the rotating part (11) is fixed at the end of the limiting part (12) away from the opening, and the central axis of the rotating part (11) is parallel to the central axis of the limiting part (12).

3. The flexible robotic arm limiting lock structure based on rope-driven variable stiffness according to claim 2, characterized in that, The opening width of the limiting part (12) is greater than the diameter of the rotating part (11), and the limiting part (12) is provided with a slot that cooperates with the rotating part (11), and the rotating part (11) can be rotatably installed in the slot.

4. The flexible robotic arm limiting lock structure based on rope-driven variable stiffness according to claim 3, characterized in that, The elastic interlayer (2) is fixed in the slot by adhesive backing.

5. The flexible robotic arm limiting lock structure based on rope-driven variable stiffness according to claim 2, characterized in that, The rotating part (11) and the limiting part (12) are integrally formed. The end of the rotating part (11) away from the limiting part (12) is provided with an arc-shaped swing groove (13). The connection between the rotating part (11) and the limiting part (12) is provided with a through hole (14) that cooperates with the rope (3).

6. The limit locking structure for a flexible robotic arm based on rope-driven variable stiffness according to claim 5, characterized in that, The central angle range corresponding to the arc-shaped swing groove (13) is 90-120 degrees.

7. The flexible robotic arm limiting lock structure based on rope-driven variable stiffness according to claim 1, characterized in that, The elastic interlayer (2) is an interlayer structure consisting of a first polytetrafluoroethylene layer, a silicone layer, and a second polytetrafluoroethylene layer stacked sequentially.

8. The flexible robotic arm limiting lock structure based on rope-driven variable stiffness according to claim 1, characterized in that, The rope drive assembly also includes a rigid motor housing (4), the motor (5) is installed inside the rigid motor housing (4), and one end of the limiting lock assembly is fixed to the bottom inside the rigid motor housing (4).

9. A flexible robotic arm, characterized in that, It includes at least the flexible robotic arm limit lock structure based on rope-driven variable stiffness as described in any one of claims 1-8.

10. A drone, comprising a drone body, characterized in that, The drone also includes a flexible robotic arm as described in claim 9, the flexible robotic arm being mounted on the drone body.

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