Foot end assembly and space robot

Abstract

The invention relates to the technical field of space robots, and discloses a foot end assembly and a space robot. The multiple grabbing and attaching claws are arranged in the circumferential direction of the mounting base, the multiple grabbing and attaching claws are rotationally connected with the mounting base, and claw thorns are arranged on the grabbing and attaching claws; and the rotary driving assembly is rotationally arranged on the mounting base and connected with the multiple grabbing and attaching claws, when the rotary driving assembly rotates in the first direction, the rotary driving assembly drives the multiple grabbing and attaching claws to be gathered together, and when the rotary driving assembly rotates in the second direction, the rotary driving assembly drives the multiple grabbing and attaching claws to be opened. By means of high-voltage contact or claw thorn piercing, firmer grabbing and attaching can be formed, the situation that the robot slides or walks unstably is avoided, and the stability requirement for walking and climbing and attaching of the robot on complex surfaces such as the surface of a spacecraft can be met.

Description

Technical Field

[0001] This invention relates to the field of space robot technology, specifically to a foot-end component and a space robot. Background Technology

[0002] As a key piece of equipment for on-orbit servicing and maintenance, space robots are an extension of astronauts in the space environment, and their ability to move stably and operate reliably on spacecraft surfaces is crucial. The foundation for achieving this capability lies in whether the foot-end actuators can establish and maintain an effective grip on the spacecraft surface.

[0003] In existing technologies, robots with multiple locomotion modes are widely studied to achieve greater environmental adaptability. One example is a hexapod omnidirectional multi-functional lunar exploration robot, which consists of a mechanical structure and a control system. The mechanical structure comprises a circular platform and six multi-degree-of-freedom legs evenly distributed in a regular hexagonal pattern. Various functional modules can be added to the circular platform to expand its functionality. The control system uses an AVR microcontroller architecture to integrate the functional modules and the mechanical structure, forming a lunar exploration robot system. This robot has both legged crawling and wheeled rolling locomotion capabilities, moving on surfaces via its mechanical legs or wheels.

[0004] However, when facing complex surfaces such as spacecraft surfaces, the mechanical legs of the aforementioned technologies have insufficient gripping force, which can easily lead to gripping failure, causing the entire robot to become unstable, tilt, or even tip over, seriously affecting the robot's operational reliability. Summary of the Invention

[0005] To address the problem in the prior art that robots may fail to grip complex surfaces, thus affecting the reliability of robot operations, this invention provides a foot end component and a space robot that can improve the gripping force of the robot's feet on the walking surface, thereby improving the robot's operational reliability.

[0006] In a first aspect, the present invention provides a foot end assembly, comprising a mounting base; a plurality of gripping claws arranged circumferentially along the mounting base and rotatably connected to the mounting base, each gripping claw having a claw spike; and a rotation drive assembly rotatably disposed on the mounting base and connected to the plurality of gripping claws, wherein when the rotation drive assembly rotates in a first direction, the rotation drive assembly drives the plurality of gripping claws to converge towards each other, and when the rotation drive assembly rotates in a second direction, the rotation drive assembly drives the plurality of gripping claws to open towards each other.

[0007] The foot assembly of this invention is suitable for mounting on a space robot. The rotary drive assembly can drive the gripping claws to rotate, causing the claw spikes to converge and press against or penetrate the walking surface, thereby enabling the space robot to grip the walking surface. When the robot lifts its foot, the rotary drive assembly drives the gripping claws to rotate in the opposite direction, causing the claw spikes to separate and detach from the walking surface. Compared to existing mechanical legs, this invention utilizes high-pressure contact or claw spike penetration to form a more secure grip, preventing the robot from slipping or becoming unstable. This meets the stability requirements for walking and climbing on complex surfaces such as spacecraft surfaces.

[0008] Preferably, the rotary drive assembly includes a drive shaft; a cam, which is sleeved on the outside of the drive shaft and fixedly connected to it, with a plurality of protrusions evenly distributed on its outer periphery; a connecting seat, which is sleeved on the outside of the drive shaft and rotatably connected to it; a plurality of gripping claws distributed circumferentially along the drive shaft; and a plurality of reset elastic elements. When the cam rotates in a first direction, the plurality of protrusions abut against the plurality of gripping claws one by one, driving the plurality of gripping claws to rotate in a direction of convergence. The plurality of reset elastic elements are connected one by one between the connecting seat and the plurality of gripping claws, driving the plurality of gripping claws to rotate in a direction of opening. The drive shaft is used to connect a rotary power source such as a servo motor, a rotary hydraulic cylinder, or a rotary pneumatic cylinder. When the rotary drive source drives the drive shaft to rotate, the cam rotates together with the drive shaft. Under the tension of the reset elastic element, the gripper remains firmly attached to the outer contour of the cam. The gripper rotates at different angles depending on its position on the cam's outer contour. Therefore, the interaction between the cam's outer contour and the gripper converts the rotational motion of the drive shaft into the rotational motion of the gripper, thereby adjusting the gripper's extension and retraction. A single power source can drive all grippers together, resulting in a simpler and more compact rotary drive assembly structure that significantly reduces the size, weight, and power consumption of the robot's foot components.

[0009] Preferably, each of the protrusions is provided with a driving ramp, which guides the gripping claws to converge. In two adjacent protrusions, the outer diameter endpoint of the previous protrusion is connected to the inner diameter starting point of the next protrusion via the driving ramp. Initially, with the claws raised and retracted, the gripping claws are pressed tightly against the inner diameter starting point of the protrusion. As the cam rotates, the gripping claws slide towards the outer diameter endpoint, pushing them to rotate outwards and downwards, causing the claws to gradually converge and eventually penetrate or press against the walking surface, providing gripping force for the robot. When the gripping claws reach the outer diameter endpoint of the protrusion, the cam continues to rotate, and the gripping claws continue to slide along the driving ramp. Guided by the driving ramp, they slide from the outer diameter endpoint of the current protrusion to the inner diameter starting point of the next protrusion. This process forces the gripping claws to rotate in the opposite direction, raising them upwards, causing the claws to detach from the walking surface, thus completing one work cycle. This ensures the continuity of the gripping claw movement. Furthermore, the gripping step frequency can be adjusted by controlling the rotational speed of the drive shaft to adapt to different movement speed requirements.

[0010] Preferably, the driving inclined plane is shaped like an Archimedean spiral. In the polar equation of the Archimedean spiral, the polar radius ρ varies uniformly with the polar angle θ. When the cam rotates at a constant speed, the radial movement speed of the gripper moving along the driving inclined plane is constant. This allows the gripper to achieve uniform radial expansion and contraction during the reset process, avoiding rigid impacts caused by sudden acceleration changes at the beginning and end of the return stroke. This results in smoother operation of the entire foot assembly with less noise and vibration. Furthermore, the reset speed and position of the gripper are predictable at any time, facilitating precise system control and timing planning.

[0011] Preferably, when the gripping claw is pushed to its limit position by the protrusion, that is, when the gripping claw contacts the end point of the outer diameter of the protrusion, an angle of 30° to 60° is formed between the claw spike and the axis of the drive shaft. This angle range can ensure sufficient vertical penetration force and horizontal gripping force, achieving a balance between the claw spike's penetration capability and its resistance to disengagement, which is beneficial to improving the reliability of the gripping action.

[0012] Preferably, the connecting seat is provided with multiple first hook structures, and each of the gripping claws is provided with a second hook structure. The two ends of the reset elastic element are respectively provided with a first hook portion and a second hook portion, which are respectively hooked onto the first hook structure and the second hook structure. By hooking the two ends of the reset elastic element onto the connecting seat and the gripping claw, the hooking and unhooking of the reset elastic element can be made faster and easier, and it is also easier to maintain.

[0013] Preferably, the bottom of the mounting base is provided with a flexible anti-slip pad; at at least a portion of the rotation angle of the gripping claw, the distance between the tip of the claw spike and the mounting base in the axial direction of the drive shaft is less than the distance between the bottom surface of the flexible anti-slip pad and the mounting base in the axial direction of the drive shaft, that is, the tip of the claw spike is higher than the bottom surface of the flexible anti-slip pad. When walking on smooth, hard surfaces, the gripping claw can be retracted, and the flexible anti-slip pad can be used for walking, achieving efficient, stable, and non-destructive walking movement. When facing complex terrain, the claw spike can be extended to grip the walking surface. The flexible anti-slip pad can complement the gripping claw, improving the robot's terrain adaptability and enhancing safety and reliability during movement.

[0014] Preferably, the side of the flexible anti-slip pad away from the mounting base has a protruding arc-shaped surface. Such a flexible anti-slip pad provides better cushioning and shock absorption, allowing the robot to move more smoothly.

[0015] Preferably, the system further includes a first thrust bearing and a second thrust bearing, both sleeved on the outside of the drive shaft; one race of the first thrust bearing is connected to one side of the cam, and the other race is connected to the connecting seat; one race of the second thrust bearing is connected to the other side of the cam, and the other race is connected to the mounting seat. Thrust bearings are prior art, therefore their specific structure and working principle will not be described in detail here. The first thrust bearing can prevent direct friction between the connecting seat and the rotating cam, reducing the frictional torque between the cam end face and the connecting seat, thereby reducing the torque required to drive the drive shaft. The function of the second thrust bearing is similar to that of the first thrust bearing, and therefore will not be described further.

[0016] Secondly, the present invention also provides a space robot, which includes a robot body on which multiple foot-end components as described above are mounted. It is understood that the alternating movements of the multiple foot-end components enable the robot to walk continuously.

[0017] The beneficial effects of this invention are: 1. Multiple grippers are set up and claw spikes are set on the grippers. By using high pressure contact or claw spikes to penetrate, a more solid grip can be formed, avoiding the robot from slipping or walking unsteadily. This can meet the stability requirements of the robot walking and climbing on complex surfaces such as spacecraft surfaces.

[0018] 2. A single power source can drive all the grippers to move together, making the structure of the entire foot assembly simpler and more compact, which can greatly save the size, weight and power consumption of the robot's foot assembly.

[0019] 3. Through a unique cam profile design, the continuous rotational motion of the drive shaft can be converted into the gripping action of the gripper, and the continuity of the gripper's motion can be guaranteed.

[0020] 4. Flexible anti-slip pads are provided, which can complement the gripper and improve the robot's terrain adaptability. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a front view of a foot end component according to an embodiment of the present invention; Figure 2 This is a perspective view of a foot-end component according to an embodiment of the present invention; Figure 3 This is a top view of the cam according to an embodiment of the present invention; Figure 4 This is a schematic diagram showing the relative positions of the first thrust bearing and the second thrust bearing in an embodiment of the present invention. Figure 5 This is a top view of the drive shaft according to an embodiment of the present invention.

[0023] Explanation of reference numerals in the attached figures: 1-Mounting base; 2-Grip claw; 201-Claw spike; 202-Second hook structure; 3-Drive shaft; 301-Keyway; 4-Cam; 401-Protrusion; 4011-Drive inclined surface; 402-Through hole; 403-Flat key structure; 404-Limiting structure; 5-Connecting base; 501-First hook structure; 6-Reset elastic element; 601-First hook part; 602-Second hook part; 7-Flexible anti-slip pad; 8-First thrust bearing; 9-Second thrust bearing. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The following is combined Figures 1 to 5 The following describes embodiments of the present invention.

[0026] According to an embodiment of the present invention, a foot end assembly is provided, comprising a mounting base 1; a plurality of gripping claws 2, the gripping claws 2 being arranged circumferentially along the mounting base 1 and rotatably connected to the mounting base 1, each gripping claw 2 being provided with claw spikes 201; and a rotation drive assembly, the rotation drive assembly being rotatably disposed on the mounting base 1 and connected to the plurality of gripping claws 2, wherein when the rotation drive assembly rotates in a first direction, the rotation drive assembly drives the plurality of gripping claws 2 to converge towards each other, and when the rotation drive assembly rotates in a second direction, the rotation drive assembly drives the plurality of gripping claws 2 to open towards each other.

[0027] The aforementioned foot assembly is suitable for installation on a space robot. The rotary drive assembly can drive the gripper 2 to rotate, causing the claw spikes 201 to converge and press against or penetrate the walking surface, thereby enabling the space robot to grip the walking surface. When the robot lifts its foot, the rotary drive assembly drives the gripper 2 to rotate in the opposite direction, causing the claw spikes 201 to open and detach from the walking surface. Compared to existing mechanical legs, this embodiment utilizes high-pressure contact or claw spike penetration to form a more secure grip, preventing the robot from slipping or becoming unstable, and meeting the stability requirements for walking and climbing on complex surfaces such as spacecraft surfaces.

[0028] Furthermore, the same gripper 2 is provided with two claw spikes 201, and the two claw spikes 201 are parallel to each other. Providing two claw spikes 201 can improve the reliability of gripping compared to one claw spike 201. In practical applications, multiple claw spikes 201 can also be provided as needed.

[0029] Furthermore, the rotary drive assembly includes a drive shaft 3; a cam 4, which is sleeved on the outside of the drive shaft 3 and fixedly connected to the drive shaft 3, with a through hole 402 in the middle of the cam 4, two flat key structures 403 on the inner wall of the through hole 402, two keyways 301 on the outer circumferential surface of the drive shaft 3, the drive shaft 3 passing through the through hole 402 and the flat key structures 403 engaging with the keyways 301 one by one, and four protrusions 401 evenly distributed on the outer circumference of the cam 4; a connecting seat 5, which is sleeved on the outside of the drive shaft 3 and rotatably connected to the drive shaft 3; four gripping claws 2, which are spaced apart along the circumference of the drive shaft 3; and four reset elastic elements 6. When the cam 4 rotates in the first direction, the four protrusions 401 abut against the four gripping claws 2 one by one, and drive the four gripping claws 2 to rotate in a direction of mutual convergence. The four reset elastic elements 6 are connected one by one between the connecting seat 5 and the four gripping claws 2, and drive the four gripping claws 2 to rotate in a direction of mutual opening. Drive shaft 3 is used to connect to a rotary power source such as a servo motor, rotary hydraulic cylinder, or rotary pneumatic cylinder. When the rotary drive source drives drive shaft 3 to rotate, cam 4 rotates together with drive shaft 3. Under the tension of the reset elastic element 6, gripper 2 is tightly attached to the outer contour of cam 4. Gripper 2 is at different rotation angles when it is attached to different positions on the outer contour of cam 4. Therefore, through the interaction between the outer contour of cam 4 and gripper 2, the rotational motion of drive shaft 3 can be converted into the rotational motion of gripper 2, thereby adjusting the extension and retraction state of gripper 201. A single power source can drive all grippers 2 to move together. This rotary drive assembly structure is simpler and more compact, greatly saving the size, weight, and power consumption of the robot's foot assembly.

[0030] Furthermore, each of the protrusions 401 is provided with a driving inclined surface 4011, which is used to guide the gripper 2 to converge with each other; in two adjacent protrusions 401, the outer diameter end point of the upper protrusion 401 is connected to the inner diameter start point of the lower protrusion 401 through the driving inclined surface 4011, and the connection is provided with a rounded corner; the inner diameter of the protrusion 401. In the initial state, with the claw 201 raised and retracted, the gripper 2 is pressed against the inner diameter starting point of the protrusion 401. As the cam 4 rotates, the gripper 2 slides towards the outer diameter endpoint, pushing it to rotate outward and downward, causing the claw 201 to gradually converge and eventually pierce or press against the walking surface, providing gripping force for the robot. When the gripper 2 reaches the outer diameter endpoint of the protrusion 401, the cam 4 continues to rotate, and the gripper 2 continues to slide along the drive ramp 4011. Guided by the drive ramp 4011, it slides from the outer diameter endpoint of the current protrusion 401 to the inner diameter starting point of the next protrusion 401. This process forces the gripper 2 to rotate in the opposite direction and lift upward, causing the claw 201 to detach from the walking surface, thus completing one work cycle. This ensures the continuity of the gripper 2's movement. Furthermore, the gripping step frequency can be adjusted by controlling the rotation speed of the drive shaft 3 to adapt to different movement speed requirements. In this embodiment, the drive cam 4 rotates 60°, the gripper 2 retracts, and the gripping action is completed; then the drive cam 4 rotates another 30°, the gripper 2 unfolds, and the retraction action is completed.

[0031] Furthermore, the driving inclined surface 4011 is shaped like an Archimedean spiral. In the polar equation of the Archimedean spiral, the polar radius ρ varies uniformly with the polar angle θ. When the cam 4 rotates at a constant speed, the radial movement speed of the gripper 2, which moves along the driving inclined surface 4011, is constant. This allows the gripper 2 to achieve uniform radial retraction and extension during the reset process, avoiding rigid impacts caused by sudden acceleration changes at the beginning and end of the return stroke. Consequently, the entire foot assembly operates more smoothly with less noise and vibration. Moreover, the reset speed and position of the gripper 2 are predictable at any time, facilitating precise system control and timing planning.

[0032] Furthermore, when the gripping claw 2 is pushed to its limit position by the protrusion 401, that is, when the gripping claw 2 contacts the end point of the outer diameter of the protrusion 401, an angle of 30° to 60° is formed between the claw spike 201 and the axis of the drive shaft 3, specifically 45°. This angle range ensures sufficient vertical penetration force and horizontal gripping force, achieving a balance between the penetration capability and anti-disengagement capability of the claw spike 201, which is beneficial to improving the reliability of the gripping action.

[0033] Furthermore, the connecting seat 5 is provided with four first hook structures 501, and each of the gripping claws 2 is provided with a second hook structure 202. The reset elastic member 6 is a closed-loop structure, with a first hooking part 601 and a second hooking part 602 at both ends. A spring structure connects the first hooking part 601 and the second hooking part 602. The first hooking part 601 and the second hooking part 602 are respectively hooked to the first hook structure 501 and the second hook structure 202. The two ends of the reset elastic member 6 are hooked to the connecting seat 5 and the gripping claw 2, which makes the hooking and unhooking of the reset elastic member 6 faster and easier, and also easier to maintain.

[0034] Furthermore, the bottom of the mounting base 1 is equipped with a flexible anti-slip pad 7, which is made of flexible silicone material and is glued to the bottom of the mounting base 1. At a certain rotation angle of the gripper 2, the distance between the tip of the claw 201 and the mounting base 1 along the axis of the drive shaft 3 is less than the distance between the bottom surface of the flexible anti-slip pad 7 and the mounting base 1 along the axis of the drive shaft 3; that is, the tip of the claw 201 is higher than the bottom surface of the flexible anti-slip pad 7. When walking on smooth, hard surfaces, the gripper 2 can be retracted, and the flexible anti-slip pad 7 can be used for walking, achieving efficient, stable, and non-destructive walking movement. When facing complex terrain, the claw 201 can be extended to grip the walking surface. The flexible anti-slip pad 7 complements the gripper 2, improving the robot's terrain adaptability and enhancing safety and reliability during movement.

[0035] Furthermore, the side of the flexible anti-slip pad 7 furthest from the mounting base 1 has a protruding arc-shaped surface. This flexible anti-slip pad 7 has better cushioning and shock absorption capabilities, allowing the robot to move more smoothly.

[0036] Furthermore, it also includes a first thrust bearing 8 and a second thrust bearing 9, both sleeved on the outside of the drive shaft 3. Both the first thrust bearing 8 and the second thrust bearing 9 are existing thrust ball bearings, coaxial with the drive shaft 3 but not in contact with it. One race of the first thrust bearing 8 is connected to one side of the cam 4, and the other race abuts against the connecting seat 5. Specifically, the cam 4 has four limiting structures 404 on the side near the first thrust bearing 8, forming a limiting groove in which the first thrust bearing 8 is located. One race of the second thrust bearing 9 abuts against the other side of the cam 4, and the other race is connected to the mounting seat 1. Thrust bearings are existing technology; therefore, their specific structure and working principle will not be described in detail in this specification. The first thrust bearing 8 can prevent direct friction between the connecting seat 5 and the rotating cam 4, reducing the frictional torque between the end face of the cam 4 and the connecting seat 5, thereby reducing the torque required to drive the drive shaft 3. The function of the second thrust bearing 9 is similar to that of the first thrust bearing 8, and therefore will not be described further.

[0037] According to an embodiment of the present invention, another aspect provides a space robot, which includes a robot body on which a plurality of foot components as described above are mounted. It is understood that the alternating movements of the plurality of foot components can enable continuous walking of the robot.

[0038] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A foot-end component, characterized in that, include: Mounting base (1); Multiple gripping claws (2) are arranged around the circumference of the mounting base (1), and the multiple gripping claws (2) are rotatably connected to the mounting base (1). Each gripping claw (2) is provided with claw spikes (201). A rotary drive assembly is rotatably mounted on the mounting base (1) and connected to a plurality of gripping claws (2). When the rotary drive assembly rotates in a first direction, it drives the plurality of gripping claws (2) to converge together. When the rotary drive assembly rotates in a second direction, it drives the plurality of gripping claws (2) to open together.

2. A foot-end assembly according to claim 1, characterized in that, The rotation drive assembly includes: Drive shaft (3); Cam (4), the cam (4) is sleeved on the outside of the drive shaft (3) and fixedly connected to the drive shaft (3), and multiple protrusions (401) are evenly distributed on the outer periphery of the cam (4). Connecting seat (5), the connecting seat (5) is sleeved on the outside of the drive shaft (3) and rotatably connected to the drive shaft (3); The plurality of gripping claws (2) are distributed circumferentially along the drive shaft (3); Multiple reset elastic elements (6), when the cam (4) rotates toward the first direction, multiple protrusions (401) abut against multiple gripping claws (2) one by one, and drive multiple gripping claws (2) to rotate toward a direction of mutual convergence, multiple reset elastic elements (6) are connected one by one between the connecting seat (5) and multiple gripping claws (2), and drive multiple gripping claws (2) to rotate toward a direction of mutual opening.

3. A foot-end assembly according to claim 2, characterized in that, Each of the protrusions (401) is provided with a driving ramp (4011), which is used to guide the gripper (2) to come together; in two adjacent protrusions (401), the outer diameter end point of the upper protrusion (401) is connected to the inner diameter start point of the lower protrusion (401) through the driving ramp (4011).

4. A foot-end assembly according to claim 3, characterized in that, The driving inclined plane (4011) is in the shape of an Archimedean spiral.

5. A foot-end assembly according to claim 2, characterized in that, When the gripper (2) is pushed to its limit position by the protrusion (401), the claw spike (201) forms an angle of 30° to 60° with the axis of the drive shaft (3).

6. A foot-end assembly according to claim 2, characterized in that, The connecting seat (5) is provided with a plurality of first hook structures (501), and the gripping claw (2) is provided with a second hook structure (202). The two ends of the reset elastic member (6) are respectively provided with a first hook part (601) and a second hook part (602). The first hook part (601) and the second hook part (602) are respectively hooked to the first hook structure (501) and the second hook structure (202).

7. A foot-end assembly according to claim 2, characterized in that, The mounting base (1) is provided with a flexible anti-slip pad (7) at the bottom; at at least a partial rotation angle of the gripping claw (2), the distance between the tip of the claw spike (201) and the mounting base (1) in the axial direction of the drive shaft (3) is less than the distance between the bottom surface of the flexible anti-slip pad (7) and the mounting base (1) in the axial direction of the drive shaft (3).

8. A foot-end assembly according to claim 7, characterized in that, The flexible anti-slip pad (7) has a protruding arc-shaped surface on the side away from the mounting base (1).

9. A foot-end assembly according to claim 2, characterized in that, It also includes a first thrust bearing (8) and a second thrust bearing (9) both sleeved on the outside of the drive shaft (3); one of the races of the first thrust bearing (8) is connected to one side of the cam (4), and the other race is connected to the connecting seat (5); one of the races of the second thrust bearing (9) is connected to the other side of the cam (4), and the other race is connected to the mounting seat (1).

10. A space robot, comprising a robot body, characterized in that, The robot body is equipped with a plurality of foot-end components as described in any one of claims 1 to 9.

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