A Rope-Driven Dexterous Capture Robot

Abstract

The present invention discloses a dexterous capture robot based on rope drive, comprising a base, wherein a No. 1 joint is installed at each triangular part of the base, a No. 1 rod is installed on the No. 1 joint, a No. 2 joint is installed on the end of the No. 1 rod away from the No. 1 joint, a No. 2 rod is installed on the No. 2 joint, one end of the No. 2 rod extends to one side of the No. 1 joint and is installed with a No. 3 joint, and a No. 3 rod is installed on the No. 3 joint. The mechanical arm structure of the present invention is formed by three rotatable No. 1 rods, No. 2 rods, No. 3 rods and connecting joints, and the occupied space in the folded state is small, and the capture space in the unfolded and enveloped state is large. The folded states of the three mechanical arms are completely consistent and are distributed in an equilateral triangle structure on the base. The three ropes are gathered together on the base and driven by the same motor, thereby improving controllability and sensitivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of space capture, and particularly relates to a dexterous capture robot based on cable drive. Background Art

[0002] In recent years, due to the increasingly frequent space activities of humans, the number of space debris has increased rapidly, posing a serious threat to space activities, spacecraft, and astronauts. In order to address the increasingly serious problem of space debris, active measures have been taken to reduce the generation of space debris, and at the same time, new technologies and methods have been actively explored to clean up space debris to ensure the sustainability of the space environment.

[0003] Currently, common space debris cleaning technologies include laser irradiation technology, pushing technology, adsorption technology, and mechanical capture technology. Among them, mechanical capture technology is further divided into rigid capture (gripping with a robotic arm) and flexible capture (such as net capture). Rigid capture technology has been studied deeply, is flexible and convenient, and has strong manipulation ability, but it requires high control precision for the robotic arm, has complex interactions, and is prone to collisions; while the flexible capture system is light in weight, does not require precise capture positions, has a large error redundancy, and can capture rotating targets, but most of them are difficult to capture repeatedly, have difficult controllability, and low reliability. Therefore, it is of great significance to study a capture method that can combine the advantages of rigid capture and flexible capture.

[0004] Space flexible rope nets have good capture capabilities, can capture multiple rotating space debris, and achieve stable wrapping. The cable-driven flexible robotic arm can be deployed to capture large space debris under the limited space of the carrier. However, since most large space debris is in a high-speed rotating state, the capture process is likely to damage the structure of the robotic arm, and the current flexible robotic arm mechanism is relatively complex to deploy and too heavy in mass. Developing a dexterous capture robot that combines space rope nets and a cable-driven deployable flexible robotic arm can better solve these problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a dexterous capture robot based on cable drive to solve the above problems.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a dexterous capture robot based on rope drive, comprising a base, wherein a No. 1 joint is installed at each triangular part of the base, a No. 1 rod is installed on the No. 1 joint, a No. 2 joint is installed at one end of the No. 1 rod away from the No. 1 joint, a No. 2 rod is installed on the No. 2 joint, one end of the No. 2 rod extends to one side of the No. 1 joint and is installed with a No. 3 joint, a No. 3 rod is installed on the No. 3 joint, and the No. 1 rod, the No. 2 rod and the No. 3 rod are connected by the No. 1 joint, the No. 2 joint and the No. 3 joint. The turning connection shape of the No. 1 joint and the No. 3 joint is arranged in a Z shape, a motor is installed in the middle of the base and the output shaft of the motor is connected to the rope collecting disk, three ropes are wound around the rope collecting disk, and each rope passes through the No. 1 rod, the No. 2 joint, the No. 2 rod, the No. 3 joint and the No. 3 rod at an angle on the base in sequence and finally comes out, a net is fixed on the outer edges of the three No. 1 rods, the No. 2 rods and the No. 3 rods on the triangle on the base, and the net is followed by the No. 1 rod, the No. 2 rod and the No. 3 rods to open and capture them under the pulling of the ropes.

[0007] Preferably, the joint No. 1 specifically includes two mutually meshing connectors 1 and 2, and connector 1 is installed on the base, connector 2 is connected to joint No. 1, both sides of connector 1 and connector 2 are provided with mounting holes and compression springs are arranged inside the mounting holes, and both sides of connector 1 and connector 2 that are meshed and connected are provided with limiting cover 1, the rod No. 1 also includes two limiting rods and the limiting rods pass through the bearings and sliders installed on the limiting cover 1 and pass through connector 2 or connector 1 and extend from a limiting cover on the other side.

[0008] Preferably, the specific structure of joint No. 2 is supplemented with joint No. 3 compared with joint No. 1. Joint No. 3 is arranged on the inner side of limit cover No. 2 which corresponds to joint No. 1, and a hole is opened inside joint No. 3 to place an iron rod to enhance the structural strength. Joint No. 3 is coaxial with limit cover No. 2, and together with the two places, they form a mechanism for fixing the tension spring.

[0009] Preferably, the specific structure of the No. 3 joint is compared with the structure of the No. 1 joint in that the limiting angle on the No. 3 joint is greater than the limiting angle on the No. 1 joint.

[0010] The technical effects and advantages of the present invention are as follows: the mechanical arm structure of the present invention is composed of three rotatable rods, rods 1, 2 and 3, connected by connecting joints. The occupied space in the folded state is small, and the capture space in the unfolded and enveloped states is large. The folded states of the three mechanical arms are completely consistent and distributed in an equilateral triangle structure on the base. The three ropes are gathered together on the base and driven by the same motor, thereby improving controllability and sensitivity.

[0011] 2. By using cable drive, a relatively massive driver (which can be a motor) can be placed away from the end effector. The cable-driven flexible robotic arm is characterized by light weight and large deformation, and can perform motions such as bending and winding to complete tasks such as capturing space debris.

[0012] 3. By adopting a foldable / unfolding structure, the problem that the flexible robotic arm cannot capture large space debris due to space limitations of the launch vehicle can be solved.

[0013] 4. By adopting a structure that combines a cable net and a robotic arm, the capture range can be increased, precise aiming at the capture position is not required, the error redundancy is large, and the control ability is increased simultaneously to achieve efficient, precise and safe capture of small to large space debris.

[0014] 5. By adding a brush structure, the rotational speed of space debris can be slowed down, the resistance during the capture process can be reduced, and the risk of damage to the robot structure can be lowered simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 FIG. is a schematic structural diagram of the folded state of the space debris capture robot in an embodiment of the present invention;

[0016] Figure 2 FIG. is a schematic structural diagram of the retracted state of the space debris capture robot in an embodiment of the present invention;

[0017] Figure 3 FIG. is a schematic structural diagram of the deployed state of the space debris capture robot in an embodiment of the present invention;

[0018] Figure 4 FIG. is a schematic structural diagram of the connection joint between the first rod and the base of the space debris capture robot in an embodiment of the present invention;

[0019] Figure 5 FIG. is a schematic structural diagram of the second joint of the space debris capture robot in an embodiment of the present invention;

[0020] Figure 6 FIG. is a schematic structural diagram of the third joint of the space debris capture robot in an embodiment of the present invention;

[0021] Figure 7 FIG. is a schematic structural diagram of the limit cover in the first joint of the space debris capture robot in an embodiment of the present invention;

[0022] Figure 8 FIG. is a schematic structural diagram of the structure in the second joint of the space debris capture robot in an embodiment of the present invention;

[0023] Figure 9 FIG. is a schematic structural diagram of the limit cover in the third joint of the space debris capture robot in an embodiment of the present invention.

[0024] Figure 10 This is a schematic diagram of the limiting cover and hook deployment movement structure in the second joint of the space debris capture robot in the embodiment of the present invention.

[0025] Figure 11 This is a schematic diagram of the limiting cover and hook envelope movement structure in the second joint of the space debris capture robot in the embodiment of the present invention.

[0026] Figure 12 This is a schematic diagram of the rope installation structure in the embodiment of the present invention.

[0027] In the figure: 1, base; 2, rope winding disc; 3, first rod; 4, second rod; 5, third rod; 6, first joint; 7, second joint; 8, third joint; 9, net; 10, connector one; 11, connector two; 12, compression spring; 13, slider; 14, first limiting cover; 15, bearing; 16, limiting rod; 17, tension spring; 18, hook; 19, second limiting cover; 20, third limiting cover; 21, connection hole; 22, first arc-shaped groove; 23, second arc-shaped groove; 24, third arc-shaped groove; 25, slider groove; 26, compression spring hole position; 27, iron rod; 28, hook column Specific embodiments

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] The present invention provides a dexterous capture robot based on rope drive as shown in the figure, including a base 1. First joints 6 are installed at the three corners of the base 1. A first rod 3 is installed on the first joint 6. A second joint 7 is installed at the end of the first rod 3 away from the first joint 6. A second rod 4 is installed on the second joint 7. One end of the second rod 4 extends to one side of the first joint 6 and a third joint 8 is installed. A third rod 5 is installed on the third joint 8. The first rod 3, the second rod 4 and the third rod 5 are arranged in a Z-shaped configuration through the turning connections of the first joint 6, the second joint 7 and the third joint 8. A motor is installed in the middle of the base 1 and the output shaft of the motor is drivingly connected to a rope winding disc 2. Three ropes are wound and connected to the rope winding disc 2, and each rope sequentially passes through the first rod 3, the second joint 7, the second rod 4, the third joint 8 and the third rod 5 at one corner of the base 1 and finally passes out. A net 9 is sleeved and fixed on the outer edges of the three first rods 3, the second rods 4 and the third rods 5 on the three corners of the base 1 and realizes opening and capturing under the pulling of the ropes by following the first rod 3, the second rod 4 and the third rod 5.

[0030] Specifically, the first joint 6 specifically includes two meshing connectors one 10 and connector two 11, and the connector one 10 is installed on the base 1. The connector two 11 is connected to the first joint 6. Installation holes are provided on both sides of the connector one 10 and the connector two 11, and compression springs 12 are arranged inside the installation holes. Limiting covers one 14 are provided on both sides where the connector one 10 and the connector two 11 are meshed and connected. The first rod 3 further includes two limiting rods 16, and the limiting rods 16 penetrate through the bearings 15 and sliders 13 on the limiting covers one 14 and penetrate through the connector two 11 or the connector one 10 and extend out from the limiting covers one 14 on the other side.

[0031] Specifically, compared with the specific structure of the first joint 6, the second joint 7 is additionally provided with a third joint 8. The third joint 8 is arranged inside the limiting cover two 19 on the second joint 7 corresponding to the first joint 6 all the time. And a hole is provided inside the third joint 8 for placing an iron rod 27 to enhance the structural strength. The third joint 8 is coaxial with the limiting cover two 19, and they together form a mechanism for fixing the tension spring 17.

[0032] Specifically, compared with the structure of the first joint 6, the specific structure of the third joint 8 is that the limiting angle on the third joint 8 is greater than the limiting angle of the first joint 6.

[0033] Working principle: The present invention is specifically composed of three robotic arms symmetrically distributed on the base. Each robotic arm is composed of a first rod 3, a second rod 4, and a third rod 5, and they are respectively connected to each other by a first joint 6, a second joint 7, and a third joint 8 in the middle. The first rod 3, the second rod 4, and the third rod 5 are all hollow structures and can be used to place ropes. The ropes penetrate through the entire robotic arm from the top of the robotic arm, specifically as Figure 12 shown, and converge to the rope winding disc on the base. The motor works to drive the rope winding disc to rotate, thereby generating a pulling force on the ropes. Since there is an eccentricity between the ropes and the center of the joints, the pulling force of the ropes on the joints generates a rotational torque, causing relative rotation between adjacent two rods, and thus realizing the tasks from the folded state to the unfolded state and then to the enveloping state; The three robotic arms are connected by a flexible net, which moves along with the robotic arms. A brush structure is arranged on the flexible net to reduce the rotation speed of the rotating object and prevent the robotic arms from being collided.

[0034] As Figure 1 、 2 and Figure 3 shown, the calculation formulas for the total space sizes in the three states are respectively:

[0035] When folded:

[0036] After unfolding:

[0037] When enveloping:

[0038] Wherein, is the base area; L is the length of a single rod of the robotic arm; is the angle between the No. 1 rod and the base in the folded state; is the angle between the No. 1 rod and the base in the unfolded state; is the radius of the circumscribed circle formed by the base; is the radius of the circumscribed circle formed by the tops of the three robotic arms in the unfolded state;

[0039] In the folded state of the space debris capture robotic arm, all the ropes converge at the rope take-up reel 2. The ropes pass through the outside of the first joint 6 on the base 1 and enter the No. 1 rod 3, pass through the rod and then go around the outside of the second joint 7 and enter the No. 2 rod 4, pass through the rod and then go around the outside of the third joint 8 and enter the No. 3 rod 5, and finally pass through the rod. The motor installed on the base 1 drives the rope take-up reel 2 to rotate, generating a pulling force on the rope, driving the gear parts on the connectors one 10 and connectors two 11 on the first joint 6, the second joint 7, and the third joint 8 to rotate, and then driving the rods connected to the connectors to start rotating. When the rope is pulled, the rod starts to unfold from the "Z" shape; in the shown folded state, the No. 1 rod 3 forms a 45-degree angle with the base, the angle between adjacent two rods is 0 degree, and the three robotic arms converge together after folding, forming a regular triangular pyramid structure with the base 1;

[0040] As Figure 2 shown, in the unfolded state of the space debris capture robotic arm, when the robotic arm is in the unfolded state, the No. 1 rod 3 forms a 120-degree angle with the base 1, the No. 1 rod 3 forms a 180-degree angle with the No. 2 rod 4, the No. 2 rod 4 forms a 150-degree angle with the No. 3 rod 5, and the net 9 is placed inside the robotic arm.

[0041] As Figure 3 shown, in the enveloping state of the space debris capture robotic arm, when the robotic arm is fully enveloped, the No. 1 rod 3 forms a 120-degree angle with the No. 2 rod 4, and the No. 2 rod 4 forms a 150-degree angle with the No. 3 rod 5.

[0042] As Figure 4 shown, on the outside of the connector one 10 and the connector two 11, there are designed 4 symmetric spring pressing hole positions 26. The compression springs 12 are placed into the hole positions radially, the lower ends abut against the bottom ends of the spring pressing holes, and the upper ends are pressed and limited by the limiting rod 16 from the outer end radially. The symmetric compression springs 12 on both sides ensure the symmetric and stable movement on both sides of the limiting rod 16. The limiting rod 16 sequentially passes through the first arc-shaped groove 22 on the limiting cover one 14, the upper ends of the compression springs 12 (at this time, the compression springs 12 are in the compressed state), the slider 13 (the slider 13 is located in the slider groove 25 inside the gear and is used for gluing and limiting the limiting rod to prevent it from falling off), and passes through the limiting cover symmetric to the other side; the surface pattern of the limiting cover one 14 is as Figure 7As shown in the figure, the two connection holes 21 on the limit cover 14 are used to fix the gears on the first connector 10 and the second connector 11; the first connector 10 is fixed on the base, and the rope passes through the connection hole 21 on the first connector 10, bypasses the two meshing gears, and then passes through the small hole on the second connector 11 and enters the second rod. The pulling force of the rope drives the gear on the second connector 11 to rotate relative to the first connector 10; at this time, the limit rods 16 on the second connector 11 and the first connector 10 also rotate relative to each other and slide relative to each other in the first arc-shaped groove 22 of the limit cover 14 until reaching the protruding part of the track towards the outer direction of the circular diameter. The two end compression springs 12 release elastic force to push the limit rod 16 towards the track protrusion. At this time, continuing to pull the rope cannot make the joint continue to rotate, realizing the limit function; the limit angle of the first arc-shaped groove 22 of the limit cover 14 is (120 - 45) / 2 = 37.5 degrees, and the total limit angle of the relative movement between the first connector 10 and the second connector 11 is 37.5 * 2 = 70 degrees.

[0043] As Figure 5 shown in the figure, the second joint 7 is provided with hooks 18 compared with the first joint 6, and the limit cover 19 is provided with hook columns 27 compared with the limit cover 14. The two ends of the hooks 18 are provided with holes for placing iron rods 27 to strengthen the structural strength. The round holes of the hooks 18 are coaxial with the connection holes 21 on the limit cover 19 and are located between the limit cover 19 and the first connector 10, jointly forming a mechanism for fixing the tension spring 17 as Figure 11 shown in the figure; the included angle between the first rod and the second rod needs to be limited twice. The surface pattern of the limit cover 19 is as Figure 8 shown in the figure. When pulling the rope, the limit rod 16 moves in the direction as Figure 10 shown in the figure. When unfolding, the limit angle is 180 - 0 = 180 degrees. After unfolding, the second arc-shaped groove 23 moves in the direction as Figure 11 shown in the figure, ensuring that the joint cannot return to the folded state after unfolding. Then pulling the rope will make the joint continue to rotate in the same direction. The movement of the limit rod 16 will push the hook 18 and drive it to rotate together. At this time, the tension spring 17 is stretched until reaching the end of the second arc-shaped groove 23 of the limit cover 19. At this time, it is the limit angle at the envelope time, and the included angle between the first rod 3 and the second rod 4 is 120 degrees. The limit angle of the second arc-shaped groove 23 of the limit cover 19 is (180 - 120) / 2 = 30 degrees; if the envelope state is to be transitioned to the unfolded state, the rope can be changed from pulling to releasing the rope, and the tension spring 17 plays a role and releases elastic force to drive the second connector 11 to rotate reversely.

[0044] As Figure 6 shown in the figure, the third joint 8 is the same as the first joint 6, only the limit included angle is changed. The included angle between the second rod and the third rod needs to be limited once. The surface pattern of the limit cover 20 is as Figure 9As shown, the limiting angle is 150 - 0 = 150 degrees. The limiting angle of the third arc-shaped groove 24 of the limiting cover three 20 is (150 - 0) / 2 = 75 degrees, and the total limiting angle of the relative movement of the second connector 11 is 75 * 2 = 150 degrees.

[0045] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or equivalently replace some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A rope-driven dexterous capture robot, characterized in that: The invention comprises a base (1), wherein a first joint (6) is installed at each triangular part of the base (1), a first rod (3) is installed on the first joint (6), a second joint (7) is installed on one end of the first rod (3) away from the first joint (6), a second rod (4) is installed on the second joint (7), one end of the second rod (4) extends to one side of the first joint (6) and is installed with a third joint (8), a third rod (5) is installed on the third joint (8), and the first rod (3), the second rod (4) and the third rod (5) are connected by the turning connection of the first joint (6), the second joint (7) and the third joint (8). The connection is arranged in a Z-shape, a motor is installed in the middle of the base (1), and the output shaft of the motor is drivingly connected to a rope collecting disk (2), three ropes are wound and connected to the rope collecting disk (2), and each rope passes through a No. 1 rod (3), a No. 2 joint (7), a No. 2 rod (4), a No. 3 joint (8) and a No. 3 rod (5) on a corner of the base (1) in sequence and finally passes out, and a net (9) is fixedly sleeved on the outer edges of the three No. 1 rods (3), No. 2 rods (4) and No. 3 rods (5) on the upper triangle of the base (1), and follows the No. 1 rods (3), No. 2 rods (4) and No. 3 rods (5) to be pulled by the ropes to achieve opening and capturing; The joint No. 1 (6) specifically comprises two mutually meshing connectors, one (10) and one (11), and the connector one (10) is mounted on the base (1), and the connector two (11) is connected to the joint No. 1 (6). Both sides of the connector one (10) and the connector two (11) are provided with mounting holes, and compression springs (12) are arranged inside the mounting holes. Limiting covers (14) are arranged on both sides of the meshing connection between the connector one (10) and the connector two (11), and the rod No. 1 (3) further comprises two limiting rods (16), and the limiting rods (16) penetrate the bearings (15) and the slider (13) mounted on the limiting cover one (14), penetrate the connector two (11) or the connector one (10), and extend from the limiting cover one (14) on the other side.

2. The rope-driven dexterous capture robot according to claim 1, characterized in that: The specific structure of the No. 2 joint (7) is that a No. 3 joint (8) is added to the No. 1 joint (6). The No. 3 joint (8) is arranged on the inner side of the No. 2 joint (7) and the limit cover No. 1 (19) which is always corresponding to the No. 1 joint (6). A hole is opened inside the No. 3 joint (8) for placing an iron rod to enhance the structural strength. The No. 3 joint (8) is coaxial with the limit cover No. 2 (19), and together with the two places, they form a mechanism for fixing the tension spring (17).

3. The rope-driven dexterous capture robot according to claim 1, characterized in that: Compared with the structure of the No. 1 joint (6), the specific structure of the No. 3 joint (8) is that the limiting angle on the No. 3 joint (8) is greater than the limiting angle of the No. 1 joint (6).

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