CN110549358B

CN110549358B - End effector

Info

Publication number: CN110549358B
Application number: CN201910918306.8A
Authority: CN
Inventors: 任威严; 孟庆良; 马天麒; 季洪鑫; 梁建勋
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2019-09-26
Filing date: 2019-09-26
Publication date: 2021-03-30
Anticipated expiration: 2039-09-26
Also published as: CN110549358A

Abstract

The end effector comprises a body, a capturing mechanism and a dragging mechanism, wherein the capturing mechanism and the dragging mechanism are arranged in the body, the dragging mechanism is fixed with the body, the output end of the dragging mechanism is connected with the capturing mechanism, the end effector is characterized in that a deviation rectifying assembly is arranged on the capturing mechanism, and a motor of the capturing mechanism drives the deviation rectifying assembly to adjust the yaw angle of a target object to a preset range. The end effector can overcome the problems that the capturing space tolerance is small and the touch impact force is large, deviation rectification adjustment is carried out on the posture of a target object while capturing is achieved, soft contact capturing of the end effector on the target object is achieved under the condition of large tolerance, the requirement for the posture parameters of the captured object of a space station is lowered, and the capturing success rate of the target object of the space station is improved.

Description

End effector

Technical Field

The invention relates to the field of space station mechanical arms, in particular to an end effector.

Background

A space station mechanical arm is one of the major key technologies of aerospace engineering in China, and comprises a core cabin mechanical arm and an experiment cabin mechanical arm. The space station mechanical arm has the functions of cabin capture and transfer, instrument and equipment transfer and installation, astronaut operation assistance and the like. The on-orbit capture technology is an important branch of the space on-orbit service technology, and the capture of the operation target is realized by a docking mechanism or an end effector which is arranged on a space station mechanical arm or an aircraft. The end effectors installed at the two ends of the manipulator are important components of a space manipulator system, are basic and important devices for achieving functions of capturing, locking, electrical connection and the like of space station targets, and generally achieve a capturing process of the space targets through the capturing adapters of the end effectors. The successful capture of the target object by the end effector is a precondition and a key link for the core cabin mechanical arm to successfully complete other tasks of the space station.

At present, the end effectors of space station mechanical arms applied at home and abroad mainly have two types: one type is a cone-rod type, the other type is a variant isomorphic peripheral type, the two types of actuators have the problems of small tolerance, low deviation correction capability and the like in space station capturing, and the capturing success rate is low under the conditions of large tolerance or captured object posture change. With the continuous development of aerospace technology, material science and mechanical science, the tail end actuating mechanism of the mechanical arm of the space station is continuously developed. Most typically, the company MDA (MacDonald Dettwiler and Associates Ltd.) in canada develops an end effector for an international space station, which can capture a target object with a large load at the space station, but still has the problems of small capture space tolerance, large contact impact force, strict requirements on the posture and capture space of the captured object, and even capture failure.

Disclosure of Invention

The invention provides an end effector which can overcome the problems of small capturing space tolerance and large touch impact force, realize deviation rectification adjustment on the posture of a target object while capturing, realize soft contact capturing of the end effector on the target object under the condition of large tolerance, reduce the posture parameter requirements on a captured object of a space station and improve the capturing success rate of the target object of the space station.

In order to solve the technical problem, the embodiment of the invention adopts the following technical scheme:

the utility model provides an end effector, includes the body to and set up at this internal mechanism of catching and drag the mechanism, drag the mechanism and fix with the body, just drag the output of mechanism with catch the mechanism and connect, catch and be provided with the subassembly of rectifying on the mechanism, the motor of catching the mechanism drives the subassembly of rectifying is adjusted the driftage angle of target object to predetermineeing the within range.

In one possible embodiment, the deviation correcting element is arranged on a side of the catching mechanism facing away from the dragging mechanism.

According to one possible design, the deviation rectifying assembly comprises a deviation rectifying ring and a plurality of deviation rectifying steel wire ropes, the deviation rectifying ring is rotatably mounted on the capturing mechanism, and the deviation rectifying steel wire ropes are interwoven in the deviation rectifying ring and used for binding a target object.

The utility model provides a possible design, catch the mechanism and include motor, solid fixed ring, swivel becket and catch wire rope, gu fixed ring with the drive mechanism is connected, the swivel becket rotation installation is in gu fixed ring is last, just swivel becket and the ring branch of rectifying are in gu fixed ring's both sides, the output of motor is connected respectively the swivel becket with rectify the ring, the wire rope's of rectifying one end is fixed it is inboard to rectify the ring, and the other end is fixed gu fixed ring's inboard.

In a possible design, the output end of the motor is provided with a first gear, the inner side of the rotating ring is provided with a first extending plate, the lower end of the first extending plate is provided with a first rack, and the first rack is meshed with the first gear.

A possible design, the lower extreme of solid fixed ring is provided with the bearing spare, and is a plurality of the bearing spare is evenly arranged the periphery of swivel becket and with the swivel becket cooperation forms swivel becket and solid fixed ring's swivelling joint.

According to one possible design, the deviation rectifying ring is connected with the motor through a transmission mechanism, the transmission mechanism comprises a second extending plate and an outer sliding ring arranged on the periphery of the rotating ring, the upper end of the outer sliding ring is connected with the deviation rectifying ring, and the inner side of the outer sliding ring is matched with the bearing piece to form rotary connection between the outer sliding ring and the fixing ring; the output end of the motor is provided with a second gear, the second extension plate is arranged at the lower end of the outer sliding ring, and a second rack is arranged at the lower end of the second extension plate and meshed with the second gear.

One possible design, the dragging mechanism further comprises a sliding assembly, the sliding assembly comprises a sliding block and a sliding rail arranged on the inner wall of the body, and the sliding block is connected with the fixing ring through a support.

In one possible embodiment, a gap is provided between the rotary ring and the outer slide ring, through which gap the holder extends up to the stationary ring.

One possible design, drag the mechanism and still include lead screw subassembly, lead screw subassembly includes lead screw, drags motor and follower, the lead screw with the follower spiro union just the one end of lead screw with drag the motor and connect, the follower pass through the connecting plate with the slider is connected.

The embodiment of the invention has the following beneficial effects:

the end effector of the embodiment of the invention can carry out deviation rectification adjustment on the posture of the target object while capturing, realizes the soft contact capturing of the end effector on the target object under the condition of large tolerance, reduces the posture parameter requirement on the captured object of the space station and improves the capturing success rate of the target object of the space station.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The invention is further described below with reference to the accompanying drawings:

FIG. 1 is a schematic view of an end effector according to an embodiment of the present disclosure;

FIG. 2 is a schematic view of a capture mechanism;

FIG. 3 is a cross-sectional view of the capture mechanism;

FIG. 4 is a schematic cross-sectional view of a capture mechanism;

FIG. 5 is a schematic view of a deviation correcting wire rope;

fig. 6 is a schematic view of a captured wire rope.

Reference numerals: 1-body, 2-dragging mechanism, 3-capturing mechanism, 4-deviation rectifying assembly, 5-deviation rectifying ring, 6-fixing ring, 7-rotating ring, 8-outer sliding ring, 9-first extending plate, 10-first rack, 11-bearing piece, 12-gap, 13-second rack, 14-first gear, 15-second gear, 16-I-shaped connecting piece, 17-capturing steel wire rope, 18-deviation rectifying steel wire rope, 19-second extending plate, 20-first groove, 21-second groove, 22-motor, 23-V-shaped slideway, 24-screw rod, 25-follower, 26-dragging motor, 27-connecting plate, 28-sliding block, 29-sliding rail, 30-support, 31-deviation rectifying area, 32-capture region, 33-bump.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the following description of the embodiments of the present invention is provided with reference to the accompanying drawings, and it should be noted that, in the case of conflict, the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other.

Please refer to fig. 1 to 4 for an end effector according to an embodiment of the present invention. As shown in fig. 1, the end effector includes a body 1, and a capturing mechanism 3 and a dragging mechanism 2 disposed in the body 1, wherein the dragging mechanism 2 is fixed to the body 1, and an output end of the dragging mechanism 2 is connected to the capturing mechanism 3 to drag the same to move along a length direction of the body 1. Particularly, the capturing mechanism 3 is further provided with a deviation rectifying assembly 4, and the deviation rectifying assembly 4 can further constrain the target object and adjust the yaw angle of the target object to be within a preset range. Therefore, the tail end actuator can correct and adjust the posture of the target object while capturing, the posture parameter requirement on the captured object of the space station is reduced, and the capturing success rate of the target object of the space station is greatly improved.

Specifically, as shown in fig. 1, the body 1 is hollow and tubular, the dragging mechanism 2 is disposed at the bottom end thereof, and the deviation rectifying component 4 is disposed at a side of the capturing mechanism 3 opposite to the dragging mechanism 2. As for the dragging mechanism 2, it includes a lead screw assembly for dragging, and a sliding assembly for guiding and controlling stability, as shown in fig. 1, wherein the sliding assembly includes three sliding blocks 28 and three sliding rails 29 disposed on the inner wall of the body 1, the three sliding rails 29 are uniformly arranged around the circumference of the body 1 and extend along the length direction of the body 1, the sliding blocks 28 are slidably connected to the sliding rails 29, and the sliding blocks 28 are further connected to the fixing ring 6 of the above-mentioned capturing mechanism 3 through a bracket 30; the screw assembly comprises a screw 24, a dragging motor 26 and a follower 25, the screw 24 is screwed with the follower 25, one end of the screw 24 is connected with the dragging motor 26, and meanwhile, the follower 25 is connected with the three sliding blocks 28 and the bracket 3 through a connecting plate 27. Thus, in operation, the pull motor 26 may rotate the lead screw 24, and the rotation of the lead screw 24 will pull the follower 25 to move along the length thereof, so that the capturing mechanism 3 connected to the follower 25 moves in the body 1, and at the same time, the above-mentioned sliding assembly may make the capturing mechanism 3 move more smoothly.

As for the catching mechanism, as shown in fig. 2, fig. 3, fig. 4 and fig. 6, it includes a motor 22, a fixed ring 6, a rotating ring 7 and a catching wire rope 18, wherein the fixed ring 6 is disposed on the upper side of the rotating ring 7, the bottom of the fixed ring 6 is provided with a plurality of bearing pieces 11, the plurality of bearing pieces 11 are uniformly arranged, the top of the bearing piece 11 is fixed with the fixed ring 6, the lower part thereof is provided with a rotatable rotating part, the outer side wall of the rotating ring 7 is provided with a V-shaped slideway 23 corresponding to the rotating part, and the two are matched to make the rotating ring 7 hang on the bearing piece 11 and rotate along the center thereof, forming the rotary connection of the fixed ring 6 and the rotating ring. The three capturing steel wire ropes 18 are interwoven in the fixed ring 6 and the rotating ring 7, one end of any capturing steel wire rope 18 is fixed on the inner wall of the rotating ring 7, the other end of the capturing steel wire rope 18 is fixed on the inner wall of the fixed ring 6, the three capturing steel wire ropes 18 surround a triangular capturing area 32 at the center of the capturing mechanism 3, and when the rotating ring 7 rotates, the size of the capturing area 32 changes along with the three capturing steel wire ropes 18, so that the three capturing steel wire ropes 18 bind objects with different shapes and sizes. Therefore, when a target object needs to be caught, the rotating ring 7 is rotated, and the catching area 32 surrounded by the catching steel wire rope 18 can be continuously tightened until the catching steel wire rope 18 surrounds and locks the target object to stop, so that the catching is realized. In addition, the inner walls of the fixed ring 6 and the rotating ring 7 are provided with a second concave groove 21, when catching is not needed, the catching steel wire rope 18 needs to be unfolded, namely, the catching steel wire rope 18 can be attached to the inner wall after the rotating ring 7 rotates and adjusts, and at the moment, the catching steel wire rope is embedded into the second concave groove 21 and completely sunk into the catching mechanism 3. The motor 4 retreats from the screw 24 and is fixed on the follower 25, and the output end thereof is provided with a first gear 14 and a second gear 15, and the first gear 14 and the second gear 15 are an integral piece. The inner wall of the rotating ring 7 is fixed with a first extending plate 9 which is arc-shaped, is attached to the inner wall of the rotating ring 7, extends downwards and is provided with a first rack 10 at the inner side, and the first rack 10 is engaged with the first gear 14, so that the motor 22 can drive the rotating ring 7 and the first extending plate 9 to rotate.

As for the deviation rectifying assembly 4, as shown in fig. 1 to 6, the deviation rectifying mechanism includes a deviation rectifying ring 5 and a deviation rectifying wire rope 17, wherein the deviation rectifying ring 5 is disposed on the upper side of the fixed ring 6, and is also rotationally connected with the fixed ring 6 to form the deviation rectifying ring 5 and the rotating ring 7 to respectively rotate on the upper and lower sides of the fixed ring 6. Specifically, the deviation rectifying ring 5 is connected with the bearing pieces 11 through the outer sliding ring 8 to form a rotary connection, wherein the inner side of the outer sliding ring 8 is also provided with a V-shaped slideway 23 which is matched with the plurality of bearing pieces 11, so that the outer sliding ring 8 is hung on the bearing pieces 11 and can rotate along the center thereof; the outer edge of the rectification ring 5 protrudes outwards to form three convex blocks 33, the lower end of each convex block 33 is connected with the outer sliding ring 8 through an I-shaped connecting piece 16, and the rectification ring 5 and the outer sliding ring 8 are fixed relatively. Thus, when the outer slip ring 8 rotates, the rectification ring 5 also rotates in synchronization. Meanwhile, a gap 12 is formed between the outer slip ring 8 and the rotating ring 7, and the gap 12 can be passed through the holder 30, so that the holder 30 can be extended from the lower side to the fixed ring 6 and fixed with the fixed ring 6. Like the capturing steel wire rope 18, the three deviation-correcting steel wire ropes 17 are interwoven in the deviation-correcting ring 5 and the fixing ring 7, one end of any deviation-correcting steel wire rope 17 is fixed on the inner wall of the deviation-correcting ring 5, the other end of the deviation-correcting steel wire rope 17 is fixed on the inner wall of the fixing ring 6, the three deviation-correcting steel wire ropes 17 surround a triangular deviation-correcting area 31 in the center of the deviation-correcting ring 5, and when the deviation-correcting ring 5 rotates, the size of the deviation-correcting area 31 changes accordingly, so that the three deviation-correcting steel wire. Therefore, when the posture of the target object needs to be adjusted, the deviation rectifying ring 5 is rotated, the deviation rectifying area 31 surrounded by the deviation rectifying steel wire ropes 17 can be continuously tightened, one or two deviation rectifying steel wire ropes 17 contact the target object, the inclined target object is dragged to be corrected until the yaw angle of the target object is within the preset range, and deviation rectification is achieved. In addition, the inner walls of the deviation rectifying ring 5 and the fixing ring 7 are also provided with a concave first groove 20, and like a second groove 21, the deviation rectifying steel wire rope 17 can be accommodated and embedded into the first groove 20 to be completely hidden in the deviation rectifying ring 5. The inner wall of the outer sliding ring 8 is fixed with a second extending plate 19 which is also arc-shaped and is attached to the inner wall of the outer sliding ring 8, the second extending plate extends downwards and is provided with a second rack 13 at the inner side, and the second rack 13 is meshed with a second gear 15, so that the motor 22 can drive the outer sliding ring 8 and the deviation rectifying ring 5 to rotate.

Therefore, the motor 22 can be driven to complete the capturing and deviation rectifying processes at the same time, the operation is simple, the fault tolerance is large, and the real-time adjustment can be carried out according to the condition of the target object. The end effector realizes soft contact with the target object by jointly bounding the target object by the capturing steel wire rope 18 and the deviation correcting steel wire rope 17, reduces contact impact force, improves capturing success rate, and meanwhile, the deviation correcting assembly corrects the posture with large deviation to a safe capturing range, thereby greatly improving the tolerance range of the end effector.

The capturing process of the end effector is mainly divided into two steps, namely capturing, correcting and dragging the target object according to the sequence of work. Firstly, before the catching, the catching steel wire rope 18 and the deviation correcting steel wire rope 17 are respectively positioned in the second groove 21 and the first groove 20, and the target object can not be interfered to enter the body 1. In the capturing stage, after the target object enters the body 1 of the end effector, an operator can start the motor 22, the motor rotates the first gear 14 and the second gear 15 to drive the rotating ring 7 and the deviation rectifying ring 5 to rotate together, the rotation of the rotating ring 7 enables the capturing steel wire rope 18 to contract until the capturing steel wire rope 18 contracts to completely wrap the target object, the capturing process of one end of the target object is completed, meanwhile, the deviation rectifying ring 5 rotates, the deviation rectifying steel wire rope 17 contracts to limit the target object, the deviation rectifying process of the target object is completed, and the original larger pitching and yaw angle of the target object is rectified and adjusted to be within a reasonable range. And finally, dragging, wherein the screw rod 3 is driven to rotate through the rotation of the dragging motor 2, the rotation of the screw rod 3 drags the capturing mechanism 3 to the bottom of the end effector, the dragging process is completed, and the capturing of the target object is realized.

By combining the embodiment, the tail end executor of the embodiment of the invention can correct and adjust the posture of the target object while capturing, realizes the soft contact capturing of the tail end executor on the target object under the condition of large tolerance, reduces the posture parameter requirements on the captured object of the space station, and improves the capturing success rate of the target object of the space station.

In the description of the present application, the terms "mounted," "connected," "fixed," and the like are used in a broad sense, and for example, "connected" may be a fixed connection, a detachable connection, or an integral connection; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In the description herein, the description of the terms "one embodiment," "some embodiments," "specific embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An end effector comprises a body, a capturing mechanism and a dragging mechanism, wherein the capturing mechanism and the dragging mechanism are arranged in the body; the dragging mechanism is fixed with the body, and the output end of the dragging mechanism is connected with the capturing mechanism; the device is characterized in that the capturing mechanism comprises a motor, a rotating ring, a capturing steel wire rope and a deviation rectifying assembly, the deviation rectifying assembly comprises a deviation rectifying ring and a plurality of deviation rectifying steel wire ropes, and the deviation rectifying steel wire ropes are interwoven in the deviation rectifying ring; one end of the capturing steel wire rope is fixed on the inner wall of the rotating ring; the output end of the motor is connected with the rotating ring and the deviation rectifying ring, and when the capturing steel wire rope captures the target object, the deviation rectifying steel wire rope adjusts the yaw angle of the target object to be within a preset range.

2. The end effector as claimed in claim 1, wherein the deskew assembly is disposed on a side of the capture mechanism facing away from the drag mechanism.

3. The end effector as claimed in claim 1, wherein the capturing mechanism further includes a fixing ring connected to the dragging mechanism, the rotating ring is rotatably mounted on the fixing ring, the rotating ring and the deviation correcting ring are respectively disposed at two sides of the fixing ring, one end of the deviation correcting wire rope is fixed at an inner side of the deviation correcting ring, and the other end of the deviation correcting wire rope is fixed at an inner side of the fixing ring.

4. The end effector as claimed in claim 3, wherein the output end of the motor is provided with a first gear, the inner side of the rotating ring is provided with a first extending plate, the lower end of the first extending plate is provided with a first rack, and the first rack is engaged with the first gear.

5. The end effector as claimed in claim 3, wherein the lower end of the fixed ring is provided with a plurality of bearing members, and the plurality of bearing members are uniformly arranged on the periphery of the rotating ring and are matched with the rotating ring to form the rotary connection between the rotating ring and the fixed ring.

6. The end effector as claimed in claim 5, wherein the deviation rectifying ring is connected to the motor through a transmission mechanism, the transmission mechanism includes a second extending plate and an outer slip ring disposed on the outer circumference of the rotating ring, the upper end of the outer slip ring is connected to the deviation rectifying ring, and the inner side of the outer slip ring is engaged with the bearing member to form a rotational connection between the outer slip ring and the fixed ring; the output end of the motor is provided with a second gear, the second extension plate is arranged at the lower end of the outer sliding ring, and a second rack is arranged at the lower end of the second extension plate and meshed with the second gear.

7. The end effector as claimed in claim 6, wherein the dragging mechanism further comprises a sliding assembly, the sliding assembly comprises a sliding block and a sliding rail arranged on the inner wall of the body, and the sliding block is connected with the fixing ring through a bracket.

8. The end effector as claimed in claim 7, wherein a gap is provided between the rotating ring and outer slide ring, the support passing through the gap and extending up to the fixed ring.

9. The end effector as claimed in claim 7, wherein the actuator mechanism further comprises a lead screw assembly including a lead screw, an actuator motor and a follower, the lead screw being in threaded engagement with the follower and one end of the lead screw being connected to the actuator motor, the follower being connected to the slide block by a link plate.