CN117918957A - Remote movement center mechanism with adjustable center point position - Google Patents
Remote movement center mechanism with adjustable center point position Download PDFInfo
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- CN117918957A CN117918957A CN202410113795.0A CN202410113795A CN117918957A CN 117918957 A CN117918957 A CN 117918957A CN 202410113795 A CN202410113795 A CN 202410113795A CN 117918957 A CN117918957 A CN 117918957A
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- 230000007246 mechanism Effects 0.000 title claims abstract description 57
- 239000012636 effector Substances 0.000 claims abstract description 12
- 210000003857 wrist joint Anatomy 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 2
- 238000002324 minimally invasive surgery Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 230000008733 trauma Effects 0.000 description 1
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Abstract
The invention discloses a remote movement center mechanism with an adjustable center point position, which comprises: the device comprises a fixed base, an end effector, three moving pairs, four universal pairs, four revolute pairs, four connecting rods and two middle platforms, wherein the three moving pairs are used for connecting the fixed base and the end effector. The fixed base is used for supporting all other components; the moving pair is a driving pair, and guide rails of the moving pair are parallel to each other and fixed on the fixed base; the first middle platform is connected with the fixed base through three moving pairs, four universal pairs, one revolute pair and three connecting rods; the second middle platform is connected with the first middle platform through four revolute pairs and two connecting rods, wherein one revolute pair is a public pair, and one connecting rod is a public connecting rod; the end effector is coaxial with the non-common link of the intermediate platform two. When the movable pair is driven, the mechanism always rotates around the RCM point in two degrees of freedom in space, the position of the RCM point is changed along with the movement of the movable pair where the public connecting rod is positioned, and the wrist joint rehabilitation requirements of different people are met.
Description
Technical Field
The invention belongs to the technical field of space parallel robots, and particularly relates to a three-degree-of-freedom space multi-ring remote movement center mechanism with an adjustable RCM point position.
Background
In 2000, students first put forward the concept of Remote Center-of-Motion (RCM) mechanisms when researching minimally invasive surgical robotic systems, and the mechanisms can realize continuous rotational movement of an end effector around a fixed point in space at the far end of the mechanism. Thanks to this motion feature, RCM mechanisms have been widely used in surgical robotic minimally invasive surgery systems to constrain the surgical tools to perform complex procedures through small incisions, thereby reducing patient trauma and the difficulty of the procedure. In addition, RCM mechanisms play an important role in exoskeleton robots that simulate the center of human joint motion, rehabilitation robots, and haptic equipment that transmit force/torque.
Currently, there are 7 main structural implementation forms for implementing far-center motion: telecentric motion, an arc-shaped guide rail mechanism, a parallelogram link mechanism, a synchronous belt mechanism, a spherical link mechanism, a universal joint mechanism, a parallel wrist joint mechanism and a planetary gear train are realized through a control algorithm. The plane parallelogram link mechanism and the parallel wrist joint mechanism have the advantages of simple structure, excellent performance, convenience in processing and manufacturing and the like, and are mainly adopted in the prior art. However, the planar parallelogram linkage mechanism and its derivative mechanism cannot realize space telecentric motion (such as CN 113116404A, CN 112716606A, CN 114504427A, CN 111544119 a), and an additional rotation module needs to be connected in series; the parallel wrist joint mechanism has high load capacity and high precision, but has limited movement space (such as CN 114288027A, CN 115476339A and CN 108972507A), and is inconvenient in parallel structural arrangement for partial application scenes such as minimally invasive surgery and the like. In addition, for the variable requirement of the RCM point of the specific scene, the existing mechanisms are fewer, wherein the positions of the fixed RCM point are changed by the patent CN 112451102A and the patent CN 112754662B through additional adjusting structures, the structure is redundant, and the processing and manufacturing difficulties and the overall control difficulties are increased. Meanwhile, all parts of the RCM mechanism are driven by a revolute pair or a moving pair, the overall moving mass is large, and the rigidity of the mechanism is reduced. Therefore, the spatial multi-ring mechanism combining the advantages of the planar RCM mechanism and the spatial RCM mechanism, fixing linear driving and being capable of changing the position of the RCM point through the continuous degree of freedom of the mechanism has wide application prospect.
Disclosure of Invention
The space telecentric mechanism is characterized by comprising a fixed base (1), a first branched chain (2), a second branched chain (3), a third branched chain (4), a first middle platform (5), a second middle platform (6), a fourth branched chain (7) and an end effector (8).
The first branched chain (2) comprises a moving pair, a universal pair, a revolute pair and a public connecting rod; the guide rail of the moving pair is fixed on the fixed base (1); the starting end point (A) of the public connecting rod is connected with the movable pair in a universal mode through a universal pair, the middle node (B) is connected with the first middle platform (5) in a rotating mode through a revolute pair, and the tail end point (C) is connected with the second middle platform (6) in a rotating mode through a revolute pair; the second rotation axis of the first universal pair is parallel to the axes of the two pairs.
The second branched chain (3) comprises a moving pair, a universal pair and a connecting rod; the guide rail of the moving pair is fixed on the fixed base (1); the starting end point (D) of the connecting rod is connected with the movable pair in a universal way through a universal pair, and the tail end point (E) is connected with the first middle platform (5) in a universal way through a universal pair; the first rotation axis of the second universal pair is parallel to the second rotation axis of the third universal pair; the second rotation axis of the second universal pair is parallel to the first rotation axis of the third universal pair.
The third branched chain (4) comprises a moving pair, a universal pair and a connecting rod; the guide rail of the moving pair is fixed on the fixed base (1); the starting end point (F) of the connecting rod is connected with the movable pair in a universal way through a universal pair, and the tail end point (G) is connected with the first middle platform (5) in a universal way through a universal pair; the first rotation axis of the fourth universal pair is parallel to the second rotation axis of the fifth universal pair; the second rotation axis of the fourth universal pair is parallel to the first rotation axis of the fifth universal pair.
The fourth branched chain (7) comprises a revolute pair, a revolute pair and a connecting rod; the starting end point (H) of the connecting rod is rotationally connected with the first middle platform (5) through a revolute pair, and the tail end point (I) is rotationally connected with the second middle platform (6) through a revolute pair; the rotation axes of the two revolute pairs are parallel to each other; the end effector (8) is fixed to the fourth branch (7) with its axis coaxial with the axis of the fourth branch.
The first middle platform (5) and the second middle platform (6) are connected through four revolute pairs to form a parallelogram mechanism.
According to one embodiment of the invention, for example, the fixed base (1) comprises three mobile pair rails, the rail axes being parallel to each other and perpendicular to the fixed base.
According to one embodiment of the invention, for example, the second branch (3), the third branch (4) are symmetrically distributed with respect to the first branch (2) in the initial state;
According to one embodiment of the present invention, for example, the second branch (3) and the third branch (4) have the same structure, and the gimbal pair structure in the first branch (2) is the same as the gimbal pair structure in the second branch (3) and the third branch (4).
According to one embodiment of the invention, for example, the first intermediate platform (5) and the second intermediate platform (6) are connected by four revolute pairs to form a parallelogram mechanism.
According to one embodiment of the invention, for example, the first intermediate platform (5) and the second intermediate platform (6) have the same length dimension.
According to one embodiment of the invention, for example, the moving pair in the first, second and third branched chains is a driving pair; input driving is realized through a ball screw mechanism; the intersection point of the axis of the fourth branched chain and the first rotation axis of the first universal pair in the first branched chain is the RCM point of the mechanism, and when the position of the first universal pair in the first branched chain changes along with the movement of the first movable pair, the position of the RCM point also changes.
Drawings
FIG. 1 is a schematic three-dimensional structure of embodiment 1 of the present invention;
FIG. 2 is a schematic diagram of a first branched structure;
FIG. 3 is a schematic diagram of a second branched structure;
FIG. 4 is a schematic diagram of a fourth branched structure;
Fig. 5 is a three-dimensional structure of embodiment 2 of the present invention.
Detailed Description
The invention is further illustrated by the following examples:
The novel RCM point-variable spatial multi-ring remote movement center mechanism shown in FIG. 1 is specifically configured as PUR & R-2PUU-RR (wherein P represents a mobile pair and is an active driving pair of the mechanism, U represents a universal pair, and R represents a revolute pair), and comprises: the device comprises a fixed base (1), a first branched chain (2), a second branched chain (3), a third branched chain (4), a first middle platform (5), a second middle platform (6), a fourth branched chain (7) and an end effector (8). The driving pair of the mechanism is a moving pair in a first branched chain 1, a second branched chain 2 and a third branched chain 3, and when the moving pair moves, the required spatial three-degree-of-freedom movement can be realized, namely: one movement of the RCM point, and two rotational movements about the RCM point.
As shown in fig. 1 and 2, the first branched chain (2) comprises a first kinematic pair (21), a first universal pair (22), a first revolute pair (23), a second revolute pair (24) and a first common connecting rod (25), and is called as a PUR & R branched chain; the guide rail of the first moving pair (21) is fixed on the fixed base (1) and is perpendicular to the fixed base; the starting end point (A) of the first common connecting rod (25) and the first movable pair (21) form universal connection through a first universal pair (22), the middle node (B) and the middle platform I (5) form rotary connection through a first rotary pair (23), and the tail end point (C) and the middle platform II (6) form rotary connection through a second rotary pair (24); the axis of the first movable pair (21) is always perpendicular to the first rotation axis 221 of the first universal pair (22); the second rotation axis (222) of the first universal pair (22) is parallel to the axes of the first rotation pair (23) and the second rotation pair (24).
As shown in fig. 1 and 3, the second branch (3) includes a second kinematic pair (31), a second universal pair (32), a third universal pair (33), and a second link (34), and is called a PUU branch; the guide rail of the second moving pair (31) is fixed on the fixed base (1) and is perpendicular to the fixed base; the starting end point (D) of the second connecting rod (34) and the second movable pair (31) form universal connection through a second universal pair (32), and the tail end point (E) and the first middle platform (5) form universal connection through a third universal pair (33); the axis of the second movable pair (31) is always perpendicular to the first rotation axis 321 of the second universal pair (32); the first axis of rotation 321 of the second gimbal pair (32) is always parallel to the second axis of rotation 332 of the third gimbal pair (33), and the second axis of rotation 322 of the second gimbal pair (32) is always parallel to the first axis of rotation 331 of the third gimbal pair (33).
As shown in fig. 1 and 3, the third branched chain (4) includes a third kinematic pair (41), a fourth gimbal pair (42), a fifth gimbal pair (43), and a third link (44), and this branched chain is also called a PUU branched chain; the guide rail of the third moving pair (41) is fixed on the fixed base (1) and is perpendicular to the fixed base; the starting end point (F) of the third connecting rod (44) and the third movable pair (41) form universal connection through a fourth universal pair (42), and the tail end point (G) and the first middle platform (5) form universal connection through a fifth universal pair (43); the axis of the third mobile pair (41) is always perpendicular to the first rotation axis 421 of the fourth gimbal pair (42); the first axis of rotation 421 of the fourth gimbal pair (42) is always parallel to the second axis of rotation 432 of the fifth gimbal pair (43), and the second axis of rotation 422 of the fourth gimbal pair (42) is always parallel to the first axis of rotation 431 of the fifth gimbal pair (43).
As shown in fig. 1 and 4, the fourth branched chain (7) comprises a third revolute pair (71), a fourth revolute pair (72) and a fourth connecting rod (73); the starting end point (H) of the fourth connecting rod (53) is in rotary connection with the first middle platform (5) through a third revolute pair (71), and the tail end point (I) is in rotary connection with the second middle platform (6) through a fourth revolute pair (72); the axes of the third revolute pair (71) and the fourth revolute pair (72) are parallel to each other; the end effector (8) is fixed to the fourth branch (7) with its axis coaxial with the axis of the fourth branch.
The first rotation axis 221 of the first universal pair (22) is always parallel to the first rotation axis 321 of the second universal pair (32) and the first rotation axis 421 of the fourth universal pair (42); the rotation axes of the first rotating pair (23) and the rotation axes of the second rotating pair (24), the third rotating pair (71) and the fourth rotating pair (72) are always kept parallel; the distance between the axes of the first revolute pair (23) and the second revolute pair (24) is equal to that between the axes of the third revolute pair (71) and the fourth revolute pair (72), the distance between the axes of the first revolute pair (23) and the third revolute pair (71) is equal to that between the axes of the second revolute pair (24) and the fourth revolute pair (72), and the four revolute pairs form a parallelogram; the intersection point M of the first rotation axis 221 of the first universal pair (22) and the axis of the fourth branched chain (7) is the RCM point of the mechanism. The change of the RCM point position of the mechanism can be realized by driving a moving pair of the first branched chain 1 through a ball screw mechanism; the ball screw mechanism drives the moving pair of the second branched chain 2 and the third branched chain 3 to realize the space two-degree-of-freedom rotary motion of pitching and yawing of the branched chain (branched chain 4) where the end effector of the mechanism is positioned around the RCM point.
As shown in fig. 5, in embodiment 2 of the present invention, the axes of the driving pairs of the branches 1,2,3 are parallel to the first rotation axes of the connected universal pairs.
The beneficial effects of the invention are as follows: the novel space multi-ring RCM mechanism without adjusting the RCM point by means of an additional structure has the advantages of the traditional double four-bar plane RCM mechanism and the single-platform space RCM mechanism, is convenient for arrangement of the mechanism, increases the movement space of RCM movement, has simple structure, good rigidity, easy manufacture and high precision, and can be used as a human joint RCM rehabilitation mechanism.
Claims (7)
1. The space telecentric mechanism is characterized by comprising a fixed base (1), a first branched chain (2), a second branched chain (3), a third branched chain (4), a first middle platform (5), a second middle platform (6), a fourth branched chain (7) and an end effector (8);
The first branched chain (2) comprises a moving pair, a universal pair, a revolute pair and a public connecting rod; the guide rail of the moving pair is fixed on the fixed base (1); the starting end point (A) of the public connecting rod is connected with the movable pair in a universal mode through a universal pair, the middle node (B) is connected with the first middle platform (5) in a rotating mode through a revolute pair, and the tail end point (C) is connected with the second middle platform (6) in a rotating mode through a revolute pair; the second rotation axis of the first universal pair is parallel to the axes of the two rotary pairs;
The second branched chain (3) comprises a moving pair, a universal pair and a connecting rod; the guide rail of the moving pair is fixed on the fixed base (1); the starting end point (D) of the connecting rod is connected with the movable pair in a universal way through a universal pair, and the tail end point (E) is connected with the first middle platform (5) in a universal way through a universal pair; the first rotation axis of the second universal pair is parallel to the second rotation axis of the third universal pair; the second rotation axis of the second universal pair is parallel to the first rotation axis of the third universal pair;
the third branched chain (4) comprises a moving pair, a universal pair and a connecting rod; the guide rail of the moving pair is fixed on the fixed base (1); the starting end point (F) of the connecting rod is connected with the movable pair in a universal way through a universal pair, and the tail end point (G) is connected with the first middle platform (5) in a universal way through a universal pair; the first rotation axis of the fourth universal pair is parallel to the second rotation axis of the fifth universal pair; the second rotation axis of the fourth universal pair is parallel to the first rotation axis of the fifth universal pair;
The fourth branched chain (7) comprises a revolute pair, a revolute pair and a connecting rod; the starting end point (H) of the connecting rod is rotationally connected with the first middle platform (5) through a revolute pair, and the tail end point (I) is rotationally connected with the second middle platform (6) through a revolute pair; the rotation axes of the two revolute pairs are parallel to each other; the end effector (8) is fixed on the fourth branched chain (7), and the axis of the end effector is coaxial with the axis of the fourth branched chain;
the first middle platform (5) and the second middle platform (6) are connected through four revolute pairs to form a parallelogram mechanism.
2. A fixed linear drive variable RCM point spatial telecentric mechanism according to claim 1, characterized in that said fixed base (1) comprises three mobile secondary guides, the axes of which are mutually parallel and perpendicular to the fixed base.
3. A fixed linear drive variable RCM point spatial telecentric mechanism according to claim 1, characterized in that the second (3) and third (4) branches are symmetrically distributed with respect to the first (2) branch in the initial state.
4. The space telecentric mechanism with fixed linear drive and variable RCM points according to claim 1, characterized in that the second branch (3) and the third branch (4) have identical structures, and the structure of the universal pair in the first branch (2) is identical to that of the universal pair in the second branch (3) and the third branch (4).
5. A fixed linear drive variable RCM point spatial telecentric mechanism according to claim 1, wherein said first intermediate stage (5) and said second intermediate stage (6) are connected by four revolute pairs to form a parallelogram mechanism.
6. The fixed linear drive variable RCM point spatial telecentric mechanism according to claim 5, wherein the first intermediate stage (5) and the second intermediate stage (6) have the same length dimension.
7. The fixed linear drive variable RCM point spatial telecentric mechanism according to claim 1, wherein the moving pairs in the first, second, and third branches are driving pairs; input driving is realized through a ball screw mechanism; the intersection point of the axis of the fourth branched chain and the first rotation axis of the first universal pair in the first branched chain is the RCM point of the mechanism, and when the position of the first universal pair in the first branched chain changes along with the movement of the first movable pair, the position of the RCM point also changes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410113795.0A CN117918957A (en) | 2024-01-26 | 2024-01-26 | Remote movement center mechanism with adjustable center point position |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410113795.0A CN117918957A (en) | 2024-01-26 | 2024-01-26 | Remote movement center mechanism with adjustable center point position |
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| CN117918957A true CN117918957A (en) | 2024-04-26 |
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| CN202410113795.0A Pending CN117918957A (en) | 2024-01-26 | 2024-01-26 | Remote movement center mechanism with adjustable center point position |
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