Flexible joint underactuated rope-driven snakelike arm

Abstract

The invention provides a flexible joint underactuated rope-driven snakelike arm, and belongs to the field of mechanical arms. The problems that a traditional mechanical arm is prone to being damaged under stress, complex in structure, large in size and incapable of completing the coating action are solved. The device comprises a plurality of joints which are rotationally connected in sequence, and a fixed included angle is formed between the rotational connection axis of every two adjacent joints and the rotational direction, so that all the joints are spiral on the whole and are used for coating an object. Every two adjacent joints are connected through a flexible connecting piece; the tail end of each rope in one group of channels penetrates through the head-end joint rope hole, sequentially penetrates through the adjacent joint rope holes and then is fixed on the middle joint, and the tail end of each rope in the other group of channels penetrates through the head-end joint rope hole, sequentially penetrates through the adjacent joint rope holes and then is fixed on the tail-end joint; the head end joint is connected with the base; and all the rope driving assemblies are electrically connected with the upper computer. The manipulator is mainly used for grabbing operation.

Description

Technical Field

[0001] The invention belongs to the field of mechanical arms, and in particular relates to a flexible joint underactuated rope-driven serpentine arm. Background Art

[0002] Rope-driven robotic arms generally contain multiple joints in series and use ropes to simulate the tendons of organisms for driving. Unlike motor-driven methods, the driving components of rope-driven robotic arms are generally installed at the base, and the arm body can reduce the design size and reduce the structural weight. Therefore, it can be used in narrow environments such as space station cabins, nuclear power plants, or aircraft fuel tanks. At the same time, because the arm body is a purely mechanical structure, there is no need to consider the impact of harsh environments such as vacuum, extreme temperatures, and thermal radiation on electronic devices, and the application scenarios are wide. Based on the geometric configuration characteristics of rope-driven robotic arms, such robotic arms can be called rope-driven snake arms and bionic tentacles.

[0003] The joint connection structure of traditional manipulators generally uses rigid components. In contact and collision scenarios, the stress generated by structural deformation is large, which can easily have a destructive effect on the structure. In addition, the number of ropes in a general rope-driven manipulator is greater than the degree of freedom of the mechanism, resulting in complex structure and large size. Summary of the invention

[0004] In view of this, the present invention aims to propose a flexible joint under-actuated rope-driven serpentine arm to solve the problems that traditional robotic arms are easily damaged under stress, have complex structures and large sizes, and cannot complete wrapping actions.

[0005] To achieve the above object, the present invention adopts the following technical solution: a flexible joint underactuated rope-driven serpentine arm, comprising:

[0006] A plurality of joints connected in rotation in sequence, wherein the axis of rotation connection of each two adjacent joints is at a fixed angle to the rotation direction so that all the joints are spiral in shape as a whole for wrapping objects. Each two adjacent joints are connected by a flexible connector, and each joint is provided with two groups of channels symmetrically distributed on both sides relative to the rotation axis of the joint, and each group of channels is provided with a plurality of rope holes arranged at intervals;

[0007] Ropes are arranged one by one in correspondence with all rope holes and the number of ropes is less than the number of degrees of freedom of all joints. Each end of the rope in one set of channels is inserted through the rope hole of the first end joint, passes through the rope holes of the adjacent joints in sequence, and is fixed on the middle joint. Each end of the rope in another set of channels is inserted through the rope hole of the first end joint, passes through the rope holes of the adjacent joints in sequence, and is fixed on the terminal joint.

[0008] A base, on which rope driving components corresponding to all the ropes are arranged for driving each rope to move, and a head end joint is connected to the base;

[0009] Host computer, all the rope drive components are electrically connected to the host computer.

[0010] Furthermore, the joint is a vertebral segment.

[0011] Furthermore, a data line hole is provided on the vertebral segment.

[0012] Furthermore, the flexible connecting member is a flexible leaf spring, which includes a connecting portion and a bending portion. Two connecting portions are provided and are respectively connected to two ends of the bending portion, and each connecting portion is connected to a joint at a corresponding position.

[0013] Furthermore, the flexible connector is overall Z-shaped.

[0014] Furthermore, the serpentine arm also includes a visual camera, and the visual camera is electrically connected to the host computer.

[0015] Furthermore, the rope driving assembly includes a screw module and a DC motor, the rotating end of the DC motor is connected to the rotating input end of the screw module, and the movable end of the screw module is connected to the head end of the corresponding rope.

[0016] Furthermore, a pitch motor is arranged on the base, the base is connected to the head end joint through the output end of the pitch motor, and the pitch Y motor is electrically connected to the upper machine.

[0017] Furthermore, a yaw motor is provided on the base for controlling the steering of the base, and the yaw motor is electrically connected to the upper machine.

[0018] Furthermore, the number of the joints is 36, and the number of the ropes is 4.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The serpentine arm uses the method of under-actuation by having fewer ropes than joint degrees of freedom to simplify the structure while satisfying normal drive. The structural size is reduced, making the entire serpentine arm lighter;

[0021] 2. The overall shape of the serpentine arm is spiral, which can wrap around objects and complete tasks that traditional robotic arms cannot complete;

[0022] 3. The serpentine arm adopts a Z-shaped flexible leaf spring structure composed of a connecting section and a bending section. The structure is simple and practical, which can increase the passive flexibility of the serpentine arm and increase the bearing capacity. At the same time, the coordination with the rope can make the serpentine arm perform flexible movements. At the same time, the flexibility of the flexible connector and the coordination with the rope make the under-actuated mode possible;

[0023] 4. The serpentine arm can complete more complex movements through the drive of the pitch motor and its own smooth movements, so that the serpentine arm can work at any angle and any working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 This is a diagram of a flexible joint underactuated rope-driven serpentine arm in a straightened state according to the present invention;

[0026] Figure 2 It is a structural schematic diagram of a flexible joint under-actuated rope-driven serpentine arm according to the present invention;

[0027] Figure 3 It is a schematic diagram of the structure of the vertebral segment according to the present invention;

[0028] Figure 4 It is a schematic structural diagram of the flexible connector described in the present invention.

[0029] Vertebral segment 1; data cable hole 1-1; rope hole 1-2; flexible leaf spring 2; connecting part 2-1; bending part 2-2; rope 3; visual camera 4; base 5; lead screw module 6; DC motor 7; pitch motor 8; yaw motor 9. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0031] Referring to the accompanying drawings, this embodiment is described, a flexible joint underactuated rope-driven serpentine arm, comprising:

[0032] A plurality of joints connected in rotation in sequence, the axis of rotation connection of each two adjacent joints is at a fixed angle to the rotation direction so that all the joints are spiral-shaped as a whole for wrapping objects. Each two adjacent joints are connected by a flexible connector, and each joint is provided with two groups of channels symmetrically distributed on both sides relative to the rotation axis of the joint, and each group of channels is provided with a plurality of rope holes 1-2 arranged at intervals; thanks to the fact that the axis of rotation connection of adjacent joints is at a certain angle to the rotation direction so that all the joints are spiral-shaped as a whole, the overall spiral structure can perform wrapping actions and maintain a certain stability, and at the same time, with the effect of the flexible connector, a certain flexibility can be guaranteed between each two adjacent joints, which can prevent damage and have the toughness to maintain a certain shape, and can meet the requirements of different use conditions.

[0033] The ropes 3 are arranged one by one in correspondence with all the rope holes 1-2 and the number is less than the number of all the joint degrees of freedom. The ends of each rope 3 in one group of channels are inserted through the first end joint rope hole 1-2, and are fixed on the middle joint after passing through the adjacent joint rope holes 1-2 in sequence. The ends of each rope 3 in another group of channels are inserted through the first end joint rope hole 1-2, and are fixed on the terminal joint after passing through the adjacent joint rope holes 1-2 in sequence. The arrangement of ropes 3 can drive the entire serpentine arm. At the same time, the arrangement method in which the number is less than the number of joint degrees of freedom can reduce the weight and reduce the complexity of the structure. Through the cooperation with the flexible connector, a certain toughness can be maintained between each adjacent joint, so that the under-actuation method of reducing the number of ropes 3 can be possible. The method in which the ropes 3 in one group of channels are fixed at the middle joint and the ropes 3 in another group are fixed at the terminal joint can drive the serpentine arm in two parts as a whole, so that it can complete more complex flexible movements and broaden the applicable scenarios of the serpentine arm.

[0034] The visual camera 4 is fixed on the end joint; the setting of the visual camera 4 can measure the end position and posture of the serpentine arm, so that the user can understand the use status of the serpentine arm.

[0035] The base 5 is provided with rope driving components corresponding to all the ropes 3 one by one for driving each rope 3 to move, and the head end joint is connected to the base 5; the setting of the base 5 can provide an installation position for the serpentine arm.

[0036] The host computer, the visual camera 4 and all the rope drive components are electrically connected to the host computer. The host computer can control the visual camera 4 and the rope drive components to complete corresponding actions according to instructions.

[0037] In this embodiment, the joint is vertebra 1. The overall structure is a certain inclined cone structure, which makes it easier for the snake-like arm to be spiral-shaped as a whole, so that the snake-like arm can complete the covering action.

[0038] In this embodiment, a data cable hole 1-1 is provided on the vertebral segment 1. The data cable can pass through the data cable hole 1-1 without affecting the corresponding action of the serpentine arm and causing interference, which is convenient for maintaining the stability of the working state of the serpentine arm.

[0039] In this embodiment, the flexible connector is a flexible leaf spring 2, which includes a connecting portion 2-1 and a bending portion 2-2. Two connecting portions 2-1 are provided and are respectively connected to the two ends of the bending portion 2-2, and each connecting portion 2-1 is connected to a joint at a corresponding position. The bending portion 2-2 can enable the flexible connector to maintain a certain toughness as a whole, and the connecting portion 2-1 plays the role of connecting the joints.

[0040] In this embodiment, the flexible connector is in a Z-shape as a whole. This configuration is different from the general torsion spring, spring and other structures, and can well adapt to the stress state when the serpentine arm is annularly wrapped, and has strong torsion resistance, so that the reliability of the wrapping action is maintained under the drive of the rope 3.

[0041] In this embodiment, the material of the flexible leaf spring 2 is spring steel 65Mn, which increases the service life and fatigue strength.

[0042] In this embodiment, the rope driving assembly includes a lead screw module 6 and a DC motor 7, the rotating end of the DC motor 7 is connected to the rotating input end of the lead screw module 6, and the movable end of the lead screw module 6 is connected to the head end of the corresponding rope 3. The operation of the DC motor 7 can drive the lead screw in the lead screw module 6 to rotate, so that the movable end is driven to move when the lead screw rotates, and the linear movement of the movable end can pull and relax the rope, and with the flexible connector, the serpentine arm can complete the corresponding action.

[0043] In this embodiment, a pitch motor 8 is provided on the base 5, the base 5 is connected to the head end joint through the output end of the pitch motor 8, and the pitch Y motor 8 is electrically connected to the host machine. The setting of the pitch motor 8 can help the serpentine arm to perform more degrees of freedom and improve the accuracy of the alignment operation.

[0044] In this embodiment, a yaw motor 9 is provided on the base 5 to control the turning of the base 5, and the yaw motor 9 is electrically connected to the host machine. The provision of the yaw motor 9 can help the serpentine arm to perform more degrees of freedom and improve the accuracy of the alignment operation.

[0045] In this embodiment, the number of the joints is 36, and the number of the ropes 3 is 4. Two ropes 3 are arranged in one channel as a group, and corresponding driving actions can be completed through each group of ropes 3.

[0046] When in use, the steering of the base 5 is adjusted by the yaw motor 9, thereby adjusting the direction of the entire serpentine arm, so as to facilitate preliminary positioning of the target. The pitch angle of the serpentine arm is controlled by the pitch motor 8, so as to facilitate a second positioning of the target.

[0047] According to the needs, the corresponding DC motor 7 is operated to drive the movable end of the lead screw module 6 to move, thereby driving the corresponding rope 3 to move, so that the rope 3 pulls or loosens the corresponding joint to move. When the rope 3 pulls, the rope 3 will lead the corresponding joint to deviate to one side, so that the flexible connector between the joints on the tension path will be compressed, and the serpentine arm will perform the corresponding spiral bending action. When the rope is loose, the flexible connector between the joints on the path will restore the deformation, thereby helping the serpentine arm to restore the deformation. The rope 3 of the serpentine arm adopts the method of connecting at the middle position and the end position, so that the serpentine arm can perform the corresponding bending action as a whole, and the joints from the head end to the middle position can perform independent actions. Of course, what is given here is a preferred form, and the connection position can be changed accordingly according to actual needs to complete the corresponding action requirements. Different driving states of different ropes 3 can help the entire serpentine arm perform various types of actions, and it has strong adaptability. At the same time, thanks to the structural form and the setting of the flexible connector, the under-driven method becomes possible. The structure of the entire serpentine arm is simplified, the weight is reduced, and with the flexible connectors, it can achieve smoother movements and higher load-bearing capacity.

[0048] The sensors, controllers and control programs that may be involved in the above description are all existing technologies and will not be described in detail here.

[0049] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. A flexible joint underactuated rope-driven serpentine arm, characterized in that: include: A plurality of joints connected in rotation in sequence, wherein the axis of rotation connection of each two adjacent joints is at a fixed angle to the rotation direction so that all the joints are spiral in shape as a whole for wrapping an object. Each two adjacent joints are connected by a flexible connector, and each joint is provided with two groups of channels symmetrically distributed on both sides relative to the rotation axis of the joint, and each group of channels is provided with a plurality of rope holes (1-2) arranged at intervals; The ropes (3) are arranged in one-to-one correspondence with all the rope holes (1-2) and the number of the ropes (3) is less than the number of all the joint degrees of freedom. The end of each rope (3) in one group of channels is inserted through the first end joint rope hole (1-2), passes through the adjacent joint rope holes (1-2) in sequence, and is then fixed to the middle joint. The end of each rope (3) in another group of channels is inserted through the first end joint rope hole (1-2), passes through the adjacent joint rope holes (1-2) in sequence, and is then fixed to the terminal joint. A base (5) is provided with rope drive assemblies corresponding to all the ropes (3) for driving each rope (3) to move, and a head end joint is connected to the base (5); Host computer, all the rope drive components are electrically connected to the host computer.

2. A flexible joint underactuated rope-driven serpentine arm according to claim 1, characterized in that: The joint is a vertebra (1).

3. The flexible joint underactuated rope-driven serpentine arm according to claim 2, characterized in that: The vertebral segment (1) is provided with a data line hole (1-1).

4. A flexible joint underactuated rope-driven serpentine arm according to any one of claims 1 to 3, characterized in that: The flexible connecting member is a flexible leaf spring (2), and the flexible leaf spring (2) comprises a connecting portion (2-1) and a bending portion (2-2). Two connecting portions (2-1) are provided and are respectively connected to two ends of the bending portion (2-2), and each connecting portion (2-1) is connected to a joint at a corresponding position.

5. The flexible joint underactuated rope-driven serpentine arm according to claim 4, characterized in that: The flexible connecting piece is overall Z-shaped.

6. The flexible joint underactuated rope-driven serpentine arm according to claim 4, characterized in that: The serpentine arm also includes a visual camera (4), and the visual camera (4) is electrically connected to the host computer.

7. The flexible joint underactuated rope-driven serpentine arm according to claim 1, characterized in that: The rope drive assembly comprises a screw module (6) and a DC motor (7), wherein the rotating end of the DC motor (7) is connected to the rotating input end of the screw module (6), and the movable end of the screw module (6) is connected to the head end of the corresponding rope (3).

8. The flexible joint underactuated rope-driven serpentine arm according to claim 1, characterized in that: The base (5) is provided with a pitch motor (8), the base (5) is connected to the head end joint via the output end of the pitch motor (8), and the pitch Y motor (8) is electrically connected to the upper machine.

9. The flexible joint underactuated rope-driven serpentine arm according to claim 1, characterized in that: The base (5) is provided with a yaw motor (9) for controlling the steering of the base (5), and the yaw motor (9) is electrically connected to a host machine.

10. The flexible joint underactuated rope-driven serpentine arm according to claim 1, characterized in that: The number of the joints is 36, and the number of the ropes (3) is 4.

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