CN111150492B

CN111150492B - Single-degree-of-freedom remote motion center mechanism

Info

Publication number: CN111150492B
Application number: CN202010052990.9A
Authority: CN
Inventors: 黄龙; 刘北; 尹来容; 胡宏伟; 徐晓强; 易可夫
Original assignee: Changsha University of Science and Technology
Current assignee: Changsha University of Science and Technology
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2021-04-30
Anticipated expiration: 2040-01-17
Also published as: CN111150492A

Abstract

The invention provides a single-degree-of-freedom remote motion center mechanism which comprises a base, a movable platform, a first branched chain, a second branched chain and a terminal instrument. The first branched chain and the second branched chain are connected through two connecting rods through revolute pairs, and the base and the movable platform are rotationally connected through the first branched chain and the second branched chain. Through the connection, the tail end instrument arranged on the movable platform can rotate around the connecting line MN in the space to form a single-degree-of-freedom remote motion center mechanism. The invention has the advantages of few components, simple and reliable structure, easy processing and assembly and better rigidity, can be used as a posture adjusting mechanism of a medical micro-operator, and can also be applied to a multi-degree-of-freedom minimally invasive surgery robot.

Description

Single-degree-of-freedom remote motion center mechanism

Technical Field

The invention belongs to the field of medical instruments, and relates to an attitude adjusting mechanism for a medical robot.

Background

The minimally invasive surgery has the advantages of small wound, capability of relieving the pain of a patient, short recovery time and the like, and becomes an important development direction of the surgical surgery. When performing minimally invasive surgery, a surgical robot is usually required to assist a doctor in performing the surgery. In the process of minimally invasive surgery assisted by a surgical robot, the tail end surgical instrument at least needs to realize three-degree-of-freedom motion, namely two-degree-of-freedom rotation around a puncture hole and axial movement along the surgical instrument. Typically, this Motion mode may be implemented by a Remote-Center-Motion (RCM) mechanism. The RCM mechanism is characterized by the fact that its output member can rotate around a distal fixed point or even move along an axis passing through the fixed point, and no actual kinematic pair exists at this fixed point. The existing remote Motion center mechanism mostly adopts a serial configuration, such as a ZEUS minimally invasive surgery operation robot of US Computer Motion company, a Da Vinci Surgical robot proposed by US Intuitive Surgical, and an RCM mechanism based on steel belt transmission proposed by domestic patent No. CN 109223182A. The RCM mechanisms realize the rotation of the tail end instrument around a remote motion center or the linear movement of the tail end instrument along a RCM point, but the RCM mechanisms are formed by connecting a plurality of joints in series, so that the motion precision and the stability of the RCM mechanisms are influenced; in addition, since the structure is complicated and the mechanism size is relatively large, it is difficult to apply to a small surgical robot. The surgical robot based on the parallel three-degree-of-freedom remote motion center mechanism, which is proposed by patent number CN107049498A, has higher motion precision and better rigidity, but has a more complex structure and a larger volume.

Disclosure of Invention

The invention discloses a single-degree-of-freedom remote motion center mechanism which is simple in structure, easy to process and assemble, good in rigidity and symmetry, capable of being used as a posture adjusting mechanism of a medical micro-manipulator and further capable of being connected with a rotary table and a linear motion unit in series to form a multi-degree-of-freedom minimally invasive surgery robot.

The invention relates to a single-degree-of-freedom remote motion center mechanism which comprises a base, a movable platform, a first branched chain, a second branched chain and a terminal instrument. The first branched chain comprises a first connecting rod and a second connecting rod, the second branched chain comprises a third connecting rod and a fourth connecting rod, the first connecting rod and the third connecting rod are identical in shape, and the second connecting rod and the fourth connecting rod are identical in shape. The base is fixed, one end of the base is in rotary connection with one end of the first connecting rod through a first revolute pair J1, the other end of the first connecting rod is in rotary connection with one end of the second connecting rod through a second revolute pair J2, and the other end of the second connecting rod is in rotary connection with one end of the movable platform through a third revolute pair J3; the other end of the base and one end of the third connecting rod form a rotary connection through a fourth revolute pair J4, the other end of the third connecting rod and one end of the fourth connecting rod form a rotary connection through a fifth revolute pair J5, and the other end of the fourth connecting rod and the other end of the movable platform form a rotary connection through a sixth revolute pair J6.

The axes of the rotating pairs at the two ends of the base are parallel to each other, and the axes of the rotating pairs at the two ends of the movable platform are also parallel to each other; all the rotating pair axes of the first connecting rod 3A and the second connecting rod 3B in the first branched chain are intersected at a first fixed point M, all the rotating pair axes of the third connecting rod 4A and the fourth connecting rod 4B in the second branched chain are intersected at a second fixed point N, and a connecting line MN of the first fixed point M and the second fixed point N is perpendicular to the rotating pair axes at two ends of the base and the rotating pair axes at two ends of the movable platform.

The tail end instrument is fixedly arranged on the movable platform, and the axis of the tail end instrument is perpendicular to the connecting line MN at a point C. The projection line of the axis of the terminal instrument on the plane formed by the axes of the third revolute pair J3 and the sixth revolute pair J6 is parallel to the axes of the third revolute pair J3 and the sixth revolute pair J6, so that the terminal instrument always rotates around a connecting line MN to form a remote center of motion mechanism.

Further, a driving motor is installed at any one of the first and fourth revolute pairs J1 and J4.

Further, the distance between the two revolute pair axes on the base is equal to the distance between the two revolute pair axes on the movable platform.

Compared with the prior art, the single-degree-of-freedom remote motion center mechanism has the following advantages: (1) the movable platform of the mechanism is connected with the base through the two branched chains, so that the mechanism has higher precision and rigidity; (2) the mechanism has the advantages of fewer connecting rods, simple structure and easy miniaturization, and can be applied to a small medical operation robot system and a small micromanipulator.

Drawings

FIG. 1 is an isometric view of the mechanism of the present invention;

FIG. 2 is a schematic view of the present invention in an initial state;

FIG. 3 is a schematic view of the present invention in a closed state;

FIG. 4 is a schematic structural view of the base of the present invention;

FIG. 5 is a schematic diagram of a first branch link structure according to the present invention;

FIG. 6 is a schematic diagram of a second branched chain structure according to the present invention;

FIG. 7 is a schematic view of an embodiment of the present invention comprising three branches;

FIGS. 8 and 9 are schematic views of two further embodiments of the present invention;

in the figure: 1-base, 2-moving platform, 3A-first connecting rod, 3B-second connecting rod, 4A-third connecting rod, 4B-fourth connecting rod and 5-terminal apparatus.

Detailed Description

The single-degree-of-freedom remote motion center mechanism provided by the invention is further described in detail below with reference to the accompanying drawings and embodiments. The embodiments of the present invention have been presented for purposes of illustration and description, and are not intended to be exhaustive or limited to the invention in the form disclosed.

In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," "fourth," "fifth," and "sixth" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

As shown in fig. 1-6, a single-degree-of-freedom remote motion center mechanism of the present invention is composed of a base 1, a movable platform 2, a first branch chain 3, a second branch chain 4 and a terminal instrument 5. The first branch chain 3 comprises a first connecting rod 3A and a second connecting rod 3B, the second branch chain 4 comprises a third connecting rod 4A and a fourth connecting rod 4B, the first connecting rod 3A and the third connecting rod 4A are identical in shape, and the second connecting rod 3B and the fourth connecting rod 4B are identical in shape. The base 1 is fixed, one end of the base 1 and one end of the first connecting rod 3A form a rotary connection through a first revolute pair J1, the other end of the first connecting rod 3A and one end of the second connecting rod 3B form a rotary connection through a second revolute pair J2, and the other end of the second connecting rod 3B and one end of the movable platform 2 form a rotary connection through a third revolute pair J3; the other end of the base 1 is rotatably connected with one end of the third connecting rod 4A through a fourth revolute pair J4, the other end of the third connecting rod 4A is rotatably connected with one end of the fourth connecting rod 4B through a fifth revolute pair J5, and the other end of the fourth connecting rod 4B is rotatably connected with the other end of the movable platform 2 through a sixth revolute pair J6.

The axes of the first and fourth revolute pairs J1, J4 form a plane P1, the axes of the third and sixth revolute pairs J3, J6 form a plane P2, the axes of the first and second revolute pairs J1, J2 form a plane P3, the axes of the second and third revolute pairs J2, J3 form a plane P4, the axes of the fourth and fifth revolute pairs J4, J5 form a plane P5, and the axes of the fifth and sixth revolute pairs J5, J6 form a plane P6.

The axes of the first revolute pair J1 and the fourth revolute pair J4 at the two ends of the base 1 are parallel to each other, and the axes of the third revolute pair J3 and the sixth revolute pair J6 at the two ends of the movable platform 2 are also parallel to each other; the axes of the first revolute pair J1, the second revolute pair J2 and the third revolute pair J3 on the first link 3A and the second link 3B in the first branch chain 3 intersect at a first fixed point M, the axes of the fourth revolute pair J4, the fifth revolute pair J5 and the sixth revolute pair J6 on the third link 4A and the fourth link 4B in the second branch chain 4 intersect at a second fixed point N, and a connecting line MN between the first fixed point M and the second fixed point N is perpendicular to the revolute pair axes at both ends of the base 1 and the revolute pair axes at both ends of the movable platform 2. The first link 3A and the third link 4A rotate in the same direction with respect to the base 1, and the axes of the first revolute pair J1 and the fourth revolute pair J4 are parallel to each other, and the plane P3 and the plane P5 are parallel to each other.

The end instrument 5 is fixedly mounted on the movable platform. The axis of the distal instrument 5 perpendicularly intersects the line MN at point C, and the projection line of the axis of the distal instrument 5 on the plane P2 is parallel to the axes of the third and sixth revolute pairs J3, J6. The axis of the distal instrument 5 is at an angle in the range of 0 to 20 degrees to the plane P2.

Through the connection, the tail end instrument 5 always rotates around a point C on the fixed connecting line MN to form a remote movement center mechanism, and the point C is a remote movement center point.

Further, a driving motor may be installed at any one of the first and fourth revolute pairs J1 and J4.

Further, the distance between the two rotating pair axes on the base is equal to the distance between the two rotating pair axes on the movable platform.

In this embodiment, the minor angle subtended between plane P3 and plane P4 varies from 40 degrees to 160 degrees, with preferred initial included angles of 90 degrees and 100 degrees.

In another embodiment of the mechanism of the present invention, the base and the movable platform are connected by three or more identical branched chains, each branched chain comprises two connecting rods, and the connecting rod rotatably connected with the base in each branched chain rotates in the same direction relative to the base 1. An example containing three branches is shown in FIG. 7. The distal instrument 5 of this embodiment is still rotatable in a single degree of freedom about the connecting line MN. The embodiment has the advantages of good rigidity and strong bearing capacity.

In another embodiment of the mechanism of the present invention, the first link 3A and the third link 4A rotate in opposite directions with respect to the base 1. Fig. 8 shows an embodiment in which the first link 3A and the third link 4A are both turned inward with respect to the base 1. Fig. 9 shows an embodiment in which the first link 3A and the third link 4A are both pivoted outward with respect to the base 1.

Claims

1. A single-degree-of-freedom remote motion center mechanism comprises a base (1), a movable platform (2), a first branched chain (3), a second branched chain (4) and a terminal instrument (5); the first branch (3) comprises a first link (3A) and a second link (3B), the second branch (4) comprises a third link (4A) and a fourth link (4B), the first link (3A) and the third link (4A) have the same shape, and the second link (3B) and the fourth link (4B) have the same shape;

the base (1) is fixed, one end of the base (1) and one end of the first connecting rod (3A) form rotary connection through a first revolute pair (J1), the other end of the first connecting rod (3A) and one end of the second connecting rod (3B) form a rotary connection through a second revolute pair (J2), the other end of the second connecting rod (3B) is rotationally connected with one end of the movable platform (2) through a third revolute pair (J3), the other end of the base (1) is rotationally connected with one end of the third connecting rod (4A) through a fourth revolute pair (J4), the other end of the third connecting rod (4A) and one end of the fourth connecting rod (4B) form a rotary connection through a fifth revolute pair (J5), the other end of the fourth connecting rod (4B) is rotationally connected with the other end of the movable platform (2) through a sixth revolute pair (J6);

the axes of the rotating pairs at the two ends of the base (1) are parallel to each other, and the axes of the rotating pairs at the two ends of the movable platform (2) are also parallel to each other; all revolute pair axes on a first connecting rod (3A) and a second connecting rod (3B) in the first branch chain (3) intersect at a first fixed point (M), and all revolute pair axes on a third connecting rod (4A) and a fourth connecting rod (4B) in the second branch chain (4) intersect at a second fixed point (N);

the tail end instrument (5) is fixedly arranged on the movable platform (2), and the axis of the tail end instrument (5) is perpendicular to the connecting line (MN) and is intersected with the point (C); the projection line of the axis of the terminal instrument (5) on the plane formed by the axes of the third revolute pair (J3) and the sixth revolute pair (J6) is parallel to the axes of the third revolute pair (J3) and the sixth revolute pair (J6), so that the terminal instrument (5) always rotates around a connecting line (MN), and a remote motion center mechanism is formed.

2. The single degree of freedom remote center of motion mechanism of claim 1, wherein: and a connecting line (MN) between the first fixing point (M) and the second fixing point (N) is perpendicular to the axes of the revolute pair at the two ends of the base (1) and the axes of the revolute pair at the two ends of the movable platform (2).

3. The single degree of freedom remote center of motion mechanism of claim 1, wherein: the driving motor is installed at any one of the first rotating pair (J1) and the fourth rotating pair (J4).

4. The single degree of freedom remote center of motion mechanism of claim 1, wherein: the distance between the two rotating pair axes on the base (1) is equal to the distance between the two rotating pair axes on the movable platform (2).