A redundantly actuated high stiffness robotic mechanism

Abstract

The present application relates to the field of robot technology, and particularly relates to a high-rigidity robot mechanism with redundant drive. The purpose is to provide a high-rigidity robot mechanism with redundant drive, which should have the characteristics of large workspace, good rigidity and high precision. The technical scheme is a high-rigidity robot mechanism with redundant drive, which comprises a rack, a rotating platform rotatably positioned on the rack and a main frame structure with a work platform, and is characterized in that: it further comprises two first branches, a second branch and a third branch connected between the main frame structure and the rotating platform.

Description

Technical Field

[0001] This invention relates to the field of robotics, specifically to a high-rigidity robot mechanism with redundant drive. Background Technology

[0002] In the field of large component machining, traditional serial machine tools suffer from poor flexibility and reconfigurability, necessitating a transformation in machining methods. With technological advancements, robotic machining has gained widespread attention due to its superior flexibility. Large component machining tasks place demands on robots in terms of large workspace and high rigidity.

[0003] Currently, most industrial robots have an open-loop structure. While they offer a large workspace, they suffer from poor overall rigidity and weak load-bearing capacity, making them prone to chattering and other problems during machining. In contrast, parallel robots, which primarily utilize parallel mechanisms, offer better overall rigidity and higher load-bearing capacity, but their workspace is limited, making them suitable only for machining small components with minimal curvature changes. Therefore, to meet the demands of efficient machining of large components, it is essential to develop a high-rigidity robot mechanism with a large workspace. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a high-rigidity robot mechanism with redundant drive, which should have the characteristics of large working space, good rigidity and high precision.

[0005] The technical solution of this invention is:

[0006] A redundantly driven high-rigidity robot mechanism includes a frame, a rotary platform rotatably positioned on the frame, and a main structure with a working platform, characterized in that it further includes two first branches, a second branch, and a third branch connected between the main structure and the rotary platform.

[0007] The main structure is a quadrilateral mechanism, which includes a third link, a fourth rotary joint, a fourth link, a fifth rotary joint, a fifth link, a compound rotary joint, a second link, and a third rotary joint connected in sequence to form a closed loop;

[0008] The first branch includes, in sequence, a guide rail, a slider, a sixth rotary joint, a sixth connecting rod, and a seventh rotary joint connecting the rotary platform and the main structure;

[0009] The second branch is a composite branch, including a second rotary joint and a first connecting rod connected sequentially between the rotary platform and the composite rotary joint, and a subordinate branch connected sequentially between the rotary platform and the middle of the first connecting rod and having the same structure as the first branch.

[0010] The third branch includes, in sequence, the eighth revolute joint connecting the rotary platform and the main structure, the sleeve, the push rod, and the ninth revolute joint connecting the middle of the fifth link.

[0011] The subordinate branches include a guide rail, a slider, a sixth rotary joint, a sixth connecting rod, and a seventh rotary joint, which are sequentially connected to the middle of the rotary platform and the first connecting rod.

[0012] In the main structure, the middle part of the fourth link is connected to the fifth revolute joint, the right end of the fourth link is connected to the fourth revolute joint, and the left end of the fourth link carries the working platform.

[0013] The third link is a bent rod with an obtuse angle, the tip of which points downwards and connects to a third revolute joint; the lower end of the third link is connected to a seventh revolute joint, and the upper end of the third link is connected to a fourth revolute joint.

[0014] The left end of the second link is connected to a compound revolute joint, the right end of the second link is connected to the obtuse angle portion of the third link through a third revolute joint, and the lower middle part of the second link is connected to another seventh revolute joint that maintains a distance from the third revolute joint.

[0015] The rotary platform is rotatably positioned on the frame via a first rotary joint, and the rotation axis of the first rotary joint is arranged vertically, while the upper plane of the rotary platform remains horizontal.

[0016] The guide rails of the two first branches are fixed parallel to each other on the upper surface of the rotary platform, and the guide rail of the subordinate branch in the second branch is fixed on the upper surface of the rotary platform and parallel to the guide rail of the first branch.

[0017] The hinge lug in the compound revolute joint is fixed to the top of the first connecting rod, while the rotating shaft in the compound revolute joint passes through the ends of both the second and fifth connecting rods before engaging with the hinge lug.

[0018] The first sliding pair is formed by the cooperation of a guide rail and a slider; the second sliding pair is formed by the cooperation of a sleeve and a push rod.

[0019] The axes of the second revolute joint, the compound revolute joint, the third revolute joint, the fourth revolute joint, the fifth revolute joint, the sixth revolute joint, the seventh revolute joint, and the eighth revolute joint are all parallel to each other and perpendicular to the axis of the first revolute joint.

[0020] The first revolute joint is a drive joint, and the prismatic joints of each branch are also drive joints.

[0021] The beneficial effects of this invention are:

[0022] The robot mechanism proposed in this invention can perform four degrees of freedom motion, consisting of two rotations and two translations, driven by five drive pairs. It is a redundant drive system and features a large workspace, good rigidity, and high precision. It can be used in fields such as robot processing and heavy-duty industrial robots. Attached Figure Description

[0023] Figure 1 This is a three-dimensional structural diagram of an embodiment of the present invention.

[0024] Figure 2 This is a diagram of the main architecture in an embodiment of the present invention.

[0025] Figure 3 This is a schematic diagram of the first branch structure in an embodiment of the present invention.

[0026] Figure 4 This is a schematic diagram of the second branch structure in an embodiment of the present invention.

[0027] Figure 5 This is a schematic diagram of the third branch structure in an embodiment of the present invention.

[0028] The diagram labels are as follows: Frame 1, Rotary Platform 2, Main Frame 3, First Link 4, Compound Rotary Joint R3, Second Link 5, Third Link 6, Fourth Link 7, Fifth Link 8, Guide Rail 9, Slider 10, Sixth Link 11, Sleeve 12, Push Rod 13, First Rotary Joint R1, Second Rotary Joint R2, Compound Rotary Joint R3, Third Rotary Joint R4, Fourth Rotary Joint R5, Fifth Rotary Joint R6, Sixth Rotary Joint R7, Seventh Rotary Joint R8, Eighth Rotary Joint R9, Ninth Rotary Joint R10, First Sliding Joint P1, Second Sliding Joint P2. Detailed Implementation

[0029] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0030] Figure 1 The redundantly driven, high-rigidity robot mechanism shown includes a frame 1, a first revolute joint R1, a rotary platform 2, a main structure 3, and four branches connecting the main structure and the rotary platform. The four branches include two first branches, one second branch, and one third branch. The frame is fixed to a foundation (foundation or support frame). The rotary platform is rotatably positioned on the frame via the first revolute joint (rotation axis arranged vertically), and the upper plane of the rotary platform remains horizontal. The first revolute joint includes a circular guide rail (conventional structure, omitted in the figure) located at the top of the frame, and a slider located at the bottom of the rotary platform and cooperating with the circular guide rail. Furthermore, the frame is also equipped with a drive mechanism (existing technology, omitted in the figure) driven by a servo motor via a reducer.

[0031] Depend on Figure 2It can be seen that the main structure is a quadrilateral mechanism (preferably a parallelogram mechanism), including the third link 6, the fourth revolute joint R5, the fourth link 7, the fifth revolute joint R6, the fifth link 8, the compound revolute joint R3, the second link 5, and the third revolute joint R4 connected in sequence to form a closed loop; wherein: the third link 6 is a bent rod with an obtuse angle, specifically it is formed by fixing one end of two straight rods to form an obtuse angle, with the tip of the obtuse angle pointing downwards and connecting to the third revolute joint R4; the lower end of the third link 6 is connected to a seventh revolute joint R8, and the upper end of the third link 6 is connected to the fourth revolute joint R5. The left end of the second link 5 is connected to the compound revolute joint R3, and the right end of the second link 5 is connected to the obtuse angle portion of the third link via the third revolute joint R4. The lower middle part of the second link 5 is connected to another seventh revolute joint R8, which is spaced from the third revolute joint R4 connected to the right end of the second link 5. The middle part of the fourth link 7 is connected to the fifth revolute joint R6, and the two ends of the fifth link 8 are connected to the fifth revolute joint R6 and the compound revolute joint R3, respectively. All the revolute joint axes in the main structure (the axes of the fourth revolute joint R5, the fifth revolute joint R6, the compound revolute joint R3, and the third revolute joint R4) are parallel to each other and perpendicular to the axes of each link. Furthermore, the right end of the fourth link 7 is connected to the fourth revolute joint R5, and the left end can carry a work platform (used for mounting work equipment) for operation.

[0032] Depend on Figure 3 It can be seen that each first branch sequentially includes a guide rail 9, a slider 10 (the guide rail and slider cooperate to form a first prismatic joint P1), a sixth revolute joint R7, a sixth connecting rod 11, and a seventh revolute joint R8, all connected between the rotary platform and the main structure. In one branch, the top end of the sixth connecting rod is connected to the lower end of the third connecting rod via the seventh revolute joint R8; in the other branch, the top end of the sixth connecting rod is connected to the lower middle part of the second connecting rod 5 via the seventh revolute joint R8.

[0033] The sixth revolute joint axis is parallel to the seventh revolute joint axis and perpendicular to the first prismatic joint axis. In the two first branches, the axes of the two first prismatic joints are parallel to each other.

[0034] Depend on Figure 4It can be seen that the second branch is a compound branch, including a second revolute joint R2 and a first connecting rod 4 connected sequentially between the rotary platform and the compound revolute joint R3, and a subordinate branch connected sequentially between the rotary platform and the middle of the first connecting rod. This subordinate branch includes a guide rail 9, a slider 10 (the guide rail and slider cooperate to form a sliding joint), a sixth revolute joint R7, a sixth connecting rod 11, and a seventh revolute joint R8, all connected sequentially between the rotary platform and the middle of the first connecting rod. Obviously, the subordinate branch structure in the second branch is exactly the same as the first branch structure, and the axis of the sliding joint therein is parallel. The first prismatic joint axis runs along the first branch; all the rotary joint axes (second rotary joint axis, compound rotary joint axis, sixth rotary joint axis, and seventh rotary joint axis) in the second branch are parallel to each other and perpendicular to the prismatic joint axis; in addition, the hinge lug in the compound rotary joint R3 is fixed to the top of the first link 4 (the bottom of the first link is connected to the rotary platform through the second rotary joint), and the rotating shaft in the compound rotary joint R3 passes through the ends of the second link 5 and the fifth link 8 and then engages with the hinge lug, thereby realizing the hinge of the three links.

[0035] Depend on Figure 5 It can be seen that the third branch includes, in sequence, the eighth rotary joint R9, sleeve 12, push rod 13 (the sleeve and push rod cooperate to form the second sliding joint P2), and the ninth rotary joint R10, which are connected between the rotary platform and the main structure. Among them, the ninth rotary joint R10 is connected to the middle of the fifth link 8 of the main structure. The axis of the ninth rotary joint and the axis of the eighth rotary joint in the third branch are parallel to each other and perpendicular to the axis of the second sliding joint.

[0036] In this embodiment, the guide rails in the two first branches are fixed parallel to each other on the upper surface of the rotary platform and are parallel to the guide rails of the subordinate branches in the second branch.

[0037] In this embodiment, except for the first revolute joint, the axes of all other revolute joints are parallel to each other and perpendicular to the axis of the first revolute joint.

[0038] In this embodiment, the driving pair consists of a first revolute joint and prismatic joints on each branch; the third branch is a redundant branch, and the second prismatic joint P2 is a redundant driving pair. The revolute joint can be driven by a servo motor through a reducer (omitted in the figure), and the prismatic joint can be driven by a servo motor driving a ball screw mechanism (omitted in the figure); when the driving pair moves, the fourth link in the mechanism can perform two rotational and two prismatic four-degree-of-freedom motion.

Claims

1. A redundantly driven high-rigidity robot mechanism, comprising a frame (1), a rotary platform (2) rotatably positioned on the frame, and a main structure (3) with a working platform, characterized in that: It also includes two first branches, one second branch, and one third branch connecting the main architecture and the rotary platform; The main structure is a quadrilateral mechanism, including a third link (6), a fourth rotary joint (R5), a fourth link (7), a fifth rotary joint (R6), a fifth link (8), a compound rotary joint (R3), a second link (5), and a third rotary joint (R4) that are connected in sequence to form a closed loop. The first branch includes, in sequence, a guide rail (9), a slider (10), a sixth rotary joint (R7), a sixth connecting rod (11), and a seventh rotary joint (R8) connected between the rotary platform and the main structure. The second branch is a composite branch, including a second rotary joint (R2) and a first connecting rod (4) connected sequentially between the rotary platform and the composite rotary joint (R3), and a subordinate branch connected sequentially between the rotary platform and the middle of the first connecting rod and having the same structure as the first branch; The third branch includes, in sequence, the eighth rotary joint (R9), sleeve (12), push rod (13) connecting the rotary platform and the main structure, and the ninth rotary joint (R10) connecting the middle of the fifth link (8). The subordinate branches include a guide rail (9), a slider (10), a sixth rotary joint (R7), a sixth link (11), and a seventh rotary joint (R8) that are sequentially connected to the middle of the rotary platform and the first link. In the main structure, the middle part of the fourth link (7) is connected to the fifth rotary joint (R6), the right end of the fourth link is connected to the fourth rotary joint (R5), and the left end of the fourth link carries the working platform; The third link (6) is a bent bar with an obtuse angle, the tip of the obtuse angle pointing downwards and connected to the third revolute joint (R4); the lower end of the third link is connected to a seventh revolute joint (R8), and the upper end of the third link is connected to a fourth revolute joint (R5). The left end of the second link (5) is connected to a compound rotary joint (R3), the right end of the second link is connected to the obtuse angle part of the third link through a third rotary joint (R4), and the lower middle part of the second link is connected to another seventh rotary joint (R8) that maintains a distance from the third rotary joint.

2. The high-rigidity robot mechanism with redundant drive according to claim 1, characterized in that: The rotary platform is rotatably positioned on the frame via a first rotary joint, and the rotation axis of the first rotary joint is arranged vertically, while the upper plane of the rotary platform remains horizontal.

3. The redundantly driven high-rigidity robot mechanism according to claim 2, characterized in that: The guide rails of the two first branches are fixed parallel to each other on the upper surface of the rotary platform, and the guide rail of the subordinate branch in the second branch is fixed on the upper surface of the rotary platform and parallel to the guide rail of the first branch.

4. The high-rigidity robot mechanism with redundant drive according to claim 3, characterized in that: The hinge lug in the compound rotary joint (R3) is fixed to the top of the first link (4), and the rotating shaft in the compound rotary joint passes through the ends of the second link and the fifth link before engaging with the hinge lug.

5. The high-rigidity robot mechanism with redundant drive according to claim 4, characterized in that: The axes of the second revolute joint, the compound revolute joint, the third revolute joint, the fourth revolute joint, the fifth revolute joint, the sixth revolute joint, the seventh revolute joint, and the eighth revolute joint are all parallel to each other and perpendicular to the axis of the first revolute joint.

6. The high-rigidity robot mechanism with redundant drive according to claim 5, characterized in that: The first revolute joint is a drive joint, and the prismatic joints of each branch are also drive joints.

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