CN112757272A

CN112757272A - Flexible snakelike arm mechanical structure capable of being extended in bending mode

Info

Publication number: CN112757272A
Application number: CN201911078926.1A
Authority: CN
Inventors: 钟国梁; 彭博文; 窦炜强
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2019-11-06
Filing date: 2019-11-06
Publication date: 2021-05-07

Abstract

The invention discloses a flexible snake-shaped arm mechanical structure capable of being bent and extended, which consists of three sections, wherein the total length of the flexible snake-shaped arm mechanical structure is 1m, the flexible snake-shaped arm mechanical structure is respectively named as a first section, a second section and a third section, and the length of each section is 300 mm. The first section comprises three elastic rods (arranged at the periphery) with the length of d4 multiplied by 1200mm, one elastic rod (arranged at the center) with the length of d4 multiplied by 1200mm, four M4 hexagonal nuts, a disc 1-1, a disc 1-2 and two fixing frames 1; similarly, the second section comprises three d4 × 900mm elastic rods, three M4 hexagonal nuts, a disk 2-1, a disk 2-2 and two fixing frames 2; the third section comprises three d4 multiplied by 600mm elastic rods, three M4 hexagon nuts, a disc 3-1, a disc 3-2 and two fixing frames 3. Each elastic rod of the first section is fixedly connected with the corresponding disc of the first section through a nut, and simultaneously passes through the second section and the third section, and finally a control motor (not shown in the figure) with the bottom connected by 300mm is reserved; similarly, the second and third sections are similar in structure to the first section. Through the push-pull action of the bottom motor on each elastic rod under cooperative control, the flexible bending deformation of the snake-shaped arm is realized by utilizing the interaction generated by the push-pull distance difference of the motors among the elastic rods.

Description

Flexible snakelike arm mechanical structure capable of being extended in bending mode

Technical Field

The invention relates to a flexible snake-shaped arm mechanical structure capable of being bent and extended, in particular to a flexible detection device applied to narrow positions such as disaster relief and emergency rescue, maintenance of aero-engines and the like.

Background

The flexible snake-shaped arm has the characteristics of large length-diameter ratio, strong deformability, good accessibility and the like, has great advantages in special application scenes of nondestructive overhaul, inner cavity assembly and the like of large-scale equipment with complex structure and compact layout, and especially has wide space in the fields of aerospace, disaster relief and emergency rescue, precision machinery manufacturing and the like. For such special application scenarios, the flexible serpentine arm with redundant degrees of freedom is produced as an emerging interdisciplinary. The research of the flexible mechanical arm starts in the early 80 th 20 th century, and along with the development of the fields of military industry, aerospace, vehicles, engineering construction and the like, the requirements of complex equipment represented by airplanes on automatic production in manufacturing, assembling and overhauling are met, so that the serpentine arm with good accessibility has important practical value, and a large number of scholars are attracted to carry out deep research.

The foreign research began earlier, and in the early 80 s of the 20 th century, the main representatives thereof are: the CTARM-1 plane flexible arm adopts a motor traction rope driving mode, and the mode also becomes a mainstream driving mode of the snake-shaped arm. Then, a variable-geometry flexible snake-shaped arm composed of truss model units is disclosed, and the flexible snake-shaped arm is characterized in that the flexible snake-shaped arm is driven by a lead screw, is flexible in stretching and retracting, but is heavy and not beneficial to carrying. Compared with foreign countries, the research in China starts late, and mainly represents a connecting rod combined flexible arm and a spine flexible arm which are in the size of Hadoop; the continuous body snake-shaped arm (patent number: 201910308264.6) of the university of China and south adopts the antagonism generated by a nickel-titanium alloy rod and pneumatic artificial muscles, and has certain rigidity while realizing flexibility.

Patent number CN 110216663A has proposed a self stabilization rope and has driven snakelike arm, has solved snakelike arm and has been in certain state and will the unstability when receiving the disturbance problem, adopts the form of universal joint a lesson and a lesson series connection, with the help of the effect of motor traction rope, makes snakelike arm when will the unstability, thereby self-adaptation rotates, adjusts the direction of universal joint and reaches balanced purpose. The patent does not relate to flexible control of the robotic arm and changes in spatial attitude.

Patent No. CN 209256914U proposes a flexible mechanical arm, which uses a serial joint connection to control the direction rotation of the mechanical arm. The mechanical arm is only applied to fruit picking, and the application range is small. And the serial connection mode of the joints only allows the joints to have rotational freedom, and the space posture is greatly limited. And need install the steering wheel in joint department, increased the weight of whole arm.

In order to solve the problems, a series-connection flexible mechanical arm is developed, the cooperative working principle of superelasticity rods is adopted, and the mechanical arm is matched with a driving motor at the root part to finally realize space omnibearing multi-posture motion. And multi-degree-of-freedom bending is realized.

Disclosure of Invention

The invention aims to overcome the defects of the prior art: the problem that 360 degrees changes in spatial attitude and the driving mode is complicated can not be realized, and a flexible snake-shaped arm mechanical structure capable of being extended in a bendable mode is provided, so that the device capable of overcoming terrain difficulty in narrow positions for detection can be realized.

The invention provides a flexible and extensible flexible snake-shaped arm mechanical structure, the overall appearance structure of the device is shown in figure 1, and the device comprises (1) discs 1-1, (2) an elastic rod with d4 x 1200mm arranged in the middle, (3) three elastic rods with d4 x 1200mm arranged around, (4) M4 hexagon nuts, (5) two fixing frames 1, (6) discs 1-2, (7) discs 2-1, (8) three elastic rods with d4 x 900mm arranged on the outer ring, (9) two fixing frames 2, (10) discs 2-2, (11) discs 3-1, (12) three elastic rods with d4 x 600mm arranged on the outermost ring, (13) two fixing frames 3 and (14) discs 3-2.

The invention is mainly characterized in that the flexible arm with higher rigidity, convenient control and three degrees of freedom of space at each section is designed, and the flexible arm can enter narrow space which can not be reached.

In one embodiment, a flexible serpentine arm mechanism capable of bending elongation, is characterized by: the flexible snake-shaped arm is composed of a first section of execution mechanism, a second section of execution mechanism, a third section of execution mechanism and a control motor (not shown). The three-section executing mechanism is similar in mechanical structure, and each section of executing mechanism comprises an upper disc, a lower disc, two fixing frames, a plurality of hexagonal nuts and a plurality of elastic rods with the same specification. Firstly, four M4 hexagonal nuts are placed in four countersunk nut holes of the disc 1-1, and then an elastic rod with the diameter of d4 multiplied by 600mm is screwed into the threaded nut until the elastic rod cannot be loosened.

Furthermore, two fixing frames 1 and a disc 1-2 are sleeved at the other end of the elastic rod, and the distance between the discs 1-1 and 1-2 is 300 mm.

Preferably, the disc 1-2 is fixed, and then the four elastic rods are given a pushing force of the same magnitude in the rod direction by the driving motor at the ends of the elastic rods, and the rods will be stretched toward the front after being forced according to the characteristics of the super elastic rods. If different amounts of force are applied to the four rods, the elastic rods will bend with the disc 1-1, and here the cooperative control is involved and will not be described.

Furthermore, after the flexible serpentine arm is completely installed, 10 elastic rods are obtained at the tail end of the third section, the flexible serpentine arm can be divided into 0-3 layers from the innermost layer to the outermost layer, the 0 layer is the elastic rod penetrating through the centers of all the circular discs, the 1 st layer is three d4 multiplied by 1200mm rods for controlling the first section of actuating mechanism, the 2 nd layer is three d4 multiplied by 900mm rods for controlling the second section of actuating mechanism, and the 3 rd layer is three d4 multiplied by 600mm rods for controlling the third section of actuating mechanism.

In one embodiment, to obtain the "S" shaped bending characteristics of the flexible serpentine arm, the motor of the third section is controlled to apply a force to the three superelastic rods of layer 3 in one direction, causing the serpentine arm to bend to the right; secondly, controlling the motor of the second section to apply opposite forces to the three superelastic rods of the layer 2, and simultaneously applying a force with the same magnitude to the motor of the third layer, wherein the third section of the serpentine arm keeps bending rightwards, and the first section and the second section bend leftwards; similarly, the motor controlling the first segment will impart a rightward bending force to the three superelastic rods of layer 1 while adding the same amount of force to the motors controlling the second and third segments, so that the first segment of the serpentine arm will bend to the right while the second and third segments will remain unchanged. Namely, each space attitude can be realized through the cooperative control of each rod, thereby adapting to the change of the terrain.

Drawings

FIG. 1 is a schematic perspective view of a preferred embodiment of the present invention;

FIG. 2 is an enlarged schematic view of a first section of the serpentine arm of the present embodiment;

FIG. 3 is an enlarged schematic view of a second section of the serpentine arm of the present embodiment;

FIG. 4 is an enlarged schematic view of a third section of the serpentine arm of the present embodiment;

FIG. 5 is an enlarged schematic view of disks 1-1 and 1-2 in this embodiment;

FIG. 6 is an enlarged schematic view of disks 2-1 and 2-2 in this embodiment;

FIG. 7 is an enlarged schematic view of disks 3-1 and 3-2 in this embodiment;

fig. 8 is an enlarged schematic view of the fixing ring 1 in this embodiment;

fig. 9 is an enlarged schematic view of the fixing ring 2 in this embodiment;

fig. 10 is an enlarged view of the fixing ring 3 in this embodiment.

Sequence numbers of the drawings:

in the figure 1, (1) a disk 1-1, (2) a d 4X 1200mm elastic rod arranged in the middle, (3) three elastic rods arranged at the periphery and having a diameter of d 4X 1200mm, (4) an M4 hexagon nut, (5) two fixing frames 1, (6) a disk 1-2, (7) a disk 2-1, (8) three elastic rods arranged at the periphery and having a diameter of d 4X 900mm, (9) two fixing frames 2, (10) a disk 2-2, (11) a disk 3-1, (12) three elastic rods arranged at the outermost periphery and having a diameter of d 4X 600mm, (13) two fixing frames 3, and (14) a disk 3-2.

In FIG. 2, (11) one elastic rod with d 4X 1200mm arranged in the middle, (12) M4 hexagonal nut, (13) fixing frame 1, (14) disc 1-2, (15) three elastic rods with d 4X 1200mm arranged around, and (16) disc 1-1.

In FIG. 3, (21) M4 hexagonal nut, (22) fixing frame 2, (23) disc 2-2, (24) disc 2-1, and (25) three d 4X 900mm rods.

FIG. 4 shows (31) M4 hexagonal nut, (32) fixing frame 3, (33) disk 3-2, (34) disk 3-1, and (35) three d 4X 600mm rods.

In FIG. 5, a and b are detailed views of the disk 1-1, and c and d are detailed views of the disk 1-2.

In FIG. 6, a and b are detail views of the disk 2-1, and c and d are detail views of the disk 2-2.

In FIG. 7, a and b are detailed views of the disc 3-1, and c and d are detailed views of the disc 3-2.

Fig. 8 is a detailed view of the fixing ring 1.

Fig. 9 is a detailed view of the fixing ring 2.

Fig. 10 is a detailed view of the fixing ring 3.

Detailed Description

As shown in fig. 1, the flexible serpentine arm mechanical structure capable of bending and extending provided by the present embodiment mainly includes three sections, each section is composed of two discs, two fixing rings and a plurality of superelastic rods, and one section is sleeved on another section in a parallel connection manner, so that not only is the stiffness of the whole machine increased, but also the end control is convenient.

As shown in fig. 2, four superelastic rods are fixedly connected with the disc 1-1 through hexagon nuts, the axial direction and the radial direction are limited, excessive energy dissipation cannot occur when input force is received, the fixing ring is in a three-fork star shape, the positions of the superelastic rods can be limited, the fixing ring has certain rigidity and is light in weight, and the load capacity is effectively improved.

As shown in fig. 3 and 4, the general structure is similar to the first-segment structure shown in fig. 2, but holes through which the first-segment and second-segment superelastic rods pass are reserved in the disk and the fixed ring, and three scalloped holes are opened in the disk to reduce weight again.

As shown in fig. 5-10, the structure of two discs and a retaining ring for each segment is shown.

Claims

1. A flexible snakelike arm mechanical structure capable of being elongated in a bendable mode is characterized in that: it includes a first, second and third finger actuator and an end drive mechanism-motor (not shown). The first section of actuating mechanism comprises four elastic rods with the diameter of d4 multiplied by 1200mm, four hexagonal nuts with the diameter of M4, two fixed frames 1 and two discs 1-1 and 1-2.

2. The disks 1-1 and 1-2 of claim 1, wherein: the diameter of the disc is 25mm, the thickness of the disc is 5mm, a through hole with the diameter of d4mm is arranged in the center of the disc, through holes with the diameter of d4mm are arranged at intervals of 120 degrees around the disc, and the distance between the center of the through hole and the center of the center hole is 7.5 mm. Particularly, four through holes on the disc 1-1 are respectively provided with a counter bore nut hole with the depth of 2 mm. The distance between the disc 1-1 and the disc 1-2 is 300 mm.

3. A d4 x 1200mm flexible rod as claimed in claim 1, wherein: the elastic rod head is provided with an external thread with the length of 20mm, and the tail part of the thread is provided with a boss for axially fixing the disc 1-1. The fixing frame 1 is in a three-pointed star shape, the thickness of the fixing frame is 5mm, the fixing frame is provided with four through holes, and the distribution positions of the four through holes are consistent with the distribution positions of the discs 1-1 and 1-2.

4. A bendable elongated flexible serpentine arm mechanism second section actuator of claim 1, wherein the second section actuator, similar to the first section, comprises discs 2-1 and 2-2, two fixed mounts 2, and three d4 x 900mm flexible rods and three M4 hex nuts.

5. The second stage actuator of claim 4, wherein: the diameters of the discs 2-1 and 2-2 are 40mm, and the inner ring is provided with four through holes, and the positions of the through holes are the same as those of the discs 1-1 and 1-2. Three through holes with 120 degrees are arranged on the outer ring, and the distance between the circle center of each through hole and the circle center of the disc 2-1 is 15 mm. Particularly, three through holes of the outer ring of the disc 2-1 are provided with countersunk nut holes with the depth of 2 mm. The distance between the disks 2-1 and 2-2 is 300 mm.

6. The second stage actuator of claim 4, wherein: the three d4 x 900mm elastic rods are provided with external threads with the length of 20mm, and the tail ends of the external threads are provided with a boss for axially fixing the disc 2-1. The fixing frame 2 is in a three-pointed star shape, and the positions of through holes of an inner ring and an outer ring of the fixing frame are the same as those of the disc 2-1.

7. The third section actuator of a bendable elongated flexible serpentine arm mechanism of claim 1, wherein: it comprises three d4 x 600mm elastic rods and three M4 hexagonal threads, a disc 3-1 and a disc 3-2, and a fixed mount 3, similarly to the first and second segments.

8. The third section actuator of claim 7, wherein: the diameter of each of the discs 3-1 and 3-2 is 55mm, and four through holes are formed in the inner ring and are in the same positions as the discs 1-1 and 1-2; the middle ring is provided with three through holes, and the positions of the through holes are the same as the positions of the outer rings of the discs 2-1 and 2-2; three through holes with the interval of 120 degrees are arranged on the outer ring, the distance between the circle center of each through hole and the circle center of the disc 3-1 is 22.5mm, and the through holes are d4 mm. Particularly, three through holes of the outer ring of the disc 3-1 are provided with countersunk nut holes with the depth of 2 mm. The distance between the disks 3-1 and 3-2 is 300 mm.

9. The third section actuator of claim 7, wherein: the three d4 x 600mm elastic rods are provided with external threads with the length of 20mm, and the tail ends of the external threads are provided with a boss for axially fixing the disc 3-1. The fixing frame 3 is in a three-pointed star shape, and the positions of through holes of an inner ring and an outer ring of the fixing frame are the same as those of the discs 3-1 and 3-2.