A single-degree-of-freedom spatial remote motion center mechanism

Abstract

The present invention relates to the fields of mechanical transmission and robotics, and in particular to a single-degree-of-freedom spatial remote motion center mechanism. The mechanism comprises a base, a motion platform, and a symmetrical connecting rod group connecting the base and the motion platform; the symmetrical connecting rod group comprises a right connecting rod group and a left connecting rod group; the right connecting rod group and the left connecting rod group each have three revolute pairs whose axes intersect at one point, and the intersection points of the axes of the three revolute pairs of the right connecting rod group and the left connecting rod group are respectively PA and PB; the motion platform can achieve single-degree-of-freedom rotational motion around the line connecting PA and PB. The mechanism of the present invention has few parts, a simple structure, and good rigidity, and can ensure good motion accuracy.

Description

Technical Field

[0001] The present invention relates to the field of mechanical transmission and robotics technology, and in particular to a single-degree-of-freedom space remote motion center mechanism. Background Art

[0002] At present, in many industries at home and abroad, whether it is medical surgical robots, industrial manufacturing, variable-mode robots, aerospace and other application scenarios, it is necessary to realize rotation around the central axis of space and to avoid mechanical interference. Since mechanical structures cannot appear around the axis of rotation, it is necessary to apply a space remote motion center mechanism to realize the motion effect of the space remote motion center. For the mechanism of a space single-degree-of-freedom rotation center, such as the invention patent application with publication number CN119112370A and the name "Remote Motion Center Device and Robot System for Minimally Invasive Surgery", more than seven kinematic pairs are required, and the stiffness outside the plane of the vertical motion axis cannot be effectively guaranteed in the design. Therefore, there is an urgent need for a space remote motion center mechanism with a single degree of freedom, few kinematic pairs, a simple configuration, and high out-of-plane stiffness. Summary of the Invention

[0003] In view of the above problems, the purpose of the present invention is to provide a single-degree-of-freedom spatial remote motion center mechanism to achieve spatial remote motion with simple configuration, single degree of freedom, few kinematic pairs and high out-of-plane stiffness.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides a single-degree-of-freedom space remote motion center mechanism, comprising a base, a motion platform, and a symmetrical connecting rod group connecting the base and the motion platform;

[0006] The symmetrical connecting rod group includes a right connecting rod group and a left connecting rod group; the right connecting rod group and the left connecting rod group each have three revolute pairs whose axes intersect at one point, and the intersection points of the axes of the three revolute pairs of the right connecting rod group and the left connecting rod group are respectively PA and PB points;

[0007] The motion platform can realize single-degree-of-freedom rotational motion around the line connecting point PA and point PB.

[0008] The right connecting rod group includes a right connecting rod A and a right connecting rod B. One end of the right connecting rod A is rotatably connected to the base, and the secondary rotation axis is R1; the other end of the right connecting rod A is rotatably connected to one end of the right connecting rod B, and the secondary rotation axis is R2; the other end of the right connecting rod B is rotatably connected to the motion platform, and the secondary rotation axis is R3;

[0009] R1, R2, and R3 intersect at the PA point.

[0010] The included angle between R1 and R2 is equal to the included angle between R3 and R2.

[0011] The left connecting rod group includes a left connecting rod B and a left connecting rod A. One end of the left connecting rod A is rotatably connected to the base, and the secondary rotation axis is L1; the other end of the left connecting rod A is rotatably connected to one end of the left connecting rod B, and the secondary rotation axis is L2; ​​the other end of the left connecting rod B is rotatably connected to the motion platform, and the secondary rotation axis is L3;

[0012] L1, L2, and L3 intersect at the PB point.

[0013] The included angle between L1 and L2 is equal to the included angle between L3 and L2.

[0014] The base is fixed relative to the installation foundation, and the line connecting point PA and point PB is the axis of rotation of the equivalent motion.

[0015] By increasing the span between the PA point and the PB point, the stiffness in the direction perpendicular to the rotation axis of the motion platform is enhanced.

[0016] The rotation range of the motion platform is determined by the length of the symmetrical connecting rod group and the angle between the rotation secondary axes.

[0017] When point PA coincides with point PB, the single-degree-of-freedom spatial remote motion center mechanism is converted into a spatially centered three-degree-of-freedom remote center mechanism.

[0018] The advantages and positive effects of the present invention are as follows: In order to realize a remote center mechanism with a single degree of freedom of motion about a spatial axis while achieving high out-of-plane stiffness, the present invention proposes a single-degree-of-freedom spatial remote motion center mechanism constructed by six revolute pairs. The specific advantages are as follows:

[0019] Simplified structure and small number of moving pairs: The present invention only uses six revolving pairs to achieve single-degree-of-freedom remote rotational motion. Compared with the existing technology, the structure is simpler and the manufacturing and assembly costs are reduced. There are fewer mechanical parts and a simple connection method, which reduces wear and failure points and is suitable for high-precision, long-cycle working environments (such as medical surgical robots).

[0020] High out-of-plane stiffness: The present invention significantly enhances the stiffness perpendicular to the rotation axis through the span design of the two sets of rotation secondary axis intersection points (PA point, PB point), avoids lateral deformation during movement, and improves movement accuracy.

[0021] Large-range interference-free rotation: The motion platform can achieve large-angle rotation around the line connecting points PA and PB, and form an avoidance zone without mechanical structures around the rotation axis, which is suitable for scenarios where interference avoidance is required, such as surgical instruments and industrial robots.

[0022] Strong movement stability: The present invention adopts a symmetrical connecting rod layout (right connecting rod A, right connecting rod B, left connecting rod A, left connecting rod B), and the angles of each connecting axis are equal, ensuring uniform force during movement and reducing vibration and unbalanced load. By adjusting the connecting rod length and the rotation sub-angle, the range of motion and stiffness characteristics can be flexibly changed to adapt to different application requirements.

[0023] Wide applicability: It can be applied to medical robots (such as minimally invasive surgical instruments), industrial automation (such as welding and assembly), aerospace (such as space agencies) and other fields to meet the diverse needs of remote motion centers. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is one of the axonometric drawings of a single-degree-of-freedom spatial remote motion center mechanism of the present invention;

[0025] Figure 2 This is the second axonometric drawing of a single-degree-of-freedom spatial remote motion center mechanism of the present invention;

[0026] Figure 3 This is the third axonometric drawing of a single-degree-of-freedom spatial remote motion center mechanism of the present invention;

[0027] Figure 4 This is a schematic diagram of the intersection of axes of the present invention;

[0028] Figure 5 It is a schematic diagram of the decomposition of the kinematic pair of the present invention;

[0029] Figure 6 Schematic diagram of the minimum motion range of the present invention;

[0030] Figure 7 Schematic diagram of the maximum motion range of the present invention.

[0031] In the figure: 1. Base; 2. Right link A; 3. Right link B; 4. Motion platform; 5. Left link B; 6. Left link A; 7. Rotation avoidance area. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] See also Figures 1 to 7As shown, the present invention provides a single-degree-of-freedom spatial remote motion center mechanism, including a base 1, a motion platform 4 and a symmetrical connecting rod group connecting the base 1 and the motion platform 4; the symmetrical connecting rod group includes a right connecting rod group and a left connecting rod group; the right connecting rod group and the left connecting rod group both have three revolute pairs whose axes intersect at one point, and the intersection points of the axes of the three revolute pairs of the right connecting rod group and the left connecting rod group are PA point and PB point respectively; the motion platform 4 can realize single-degree-of-freedom rotational motion around the line connecting the PA point and the PB point.

[0034] See also Figures 4 and 5 As shown, in an embodiment of the present invention, the right side connecting rod group includes a right connecting rod A2 and a right connecting rod B3, one end of the right connecting rod A2 is rotatably connected to the base 1, and the secondary axis of rotation is R1; the other end of the right connecting rod A2 is rotatably connected to one end of the right connecting rod B3, and the secondary axis of rotation is R2; the other end of the right connecting rod B3 is rotatably connected to the motion platform 4, and the secondary axis of rotation is R3; R1, R2, and R3 intersect at point PA.

[0035] Furthermore, the included angle between R1 and R2 is equal to the included angle between R3 and R2, and the included angles of each connecting axis are equal, ensuring uniform force during movement and reducing vibration and unbalanced load.

[0036] See also Figures 4 and 5 As shown, in an embodiment of the present invention, the left side link group includes a left link B5 and a left link A6, one end of the left link A6 is rotatably connected to the base 1, and the secondary axis of rotation is L1; the other end of the left link A6 is rotatably connected to one end of the left link B5, and the secondary axis of rotation is L2; ​​the other end of the left link B5 is rotatably connected to the motion platform 4, and the secondary axis of rotation is L3; L1, L2, and L3 intersect at point PB.

[0037] Furthermore, the included angle between L1 and L2 is equal to the included angle between L3 and L2.

[0038] In this embodiment of the present invention, base 1 is fixed relative to the mounting base. Under this constraint, motion platform 4 can achieve rotational motion about the line connecting points PA and PB. In other words, the line connecting points PA and PB is the axis of rotation for equivalent motion. By increasing the distance between points PA and PB, the stiffness of motion platform 4 in a direction perpendicular to its axis of rotation is enhanced.

[0039] Furthermore, the range of motion of motion platform 4 is determined by the length of the symmetrical connecting rods and the angle between the secondary axes of rotation. Specifically, a larger angle between the secondary axes of rotation increases the range of motion, while a longer connecting rod increases the distance from the axis of equivalent motion. However, these two mechanisms are strongly coupled. By adjusting the connecting rod length and the secondary angle, the range of motion and stiffness characteristics can be flexibly adjusted to meet different application requirements.

[0040] When point PA coincides with point PB, the single-degree-of-freedom spatial remote motion center mechanism is converted into a three-degree-of-freedom spatially centered remote center mechanism.

[0041] See also Figure 6 and Figure 7 As shown, in the embodiment of the present invention, the minimum range of rotation of the motion platform 4 is α min , the maximum is α max The angle within this range is related to the dimensions and axis angle of the right, right, left, and left links A2, B3, B5, and A6. A defined, mechanically structure-free swing avoidance zone 7 can be achieved within the line connecting points PA and PB, benefiting engineering applications.

[0042] The present invention provides a single-degree-of-freedom spatial remote motion center mechanism, the working principle of which is:

[0043] The intersection of the axes of the spatial revolute pairs can realize spatially centered motion, which is equivalent to a single ball joint; at the same time, the connection line of the spatial double ball joint can equivalently produce a constraint relationship for motion around the axis. Therefore, the present invention realizes the function of the dynamic motion platform 4 for the spatial remote rotational motion relative to the base 1 by applying six connecting rods and six revolute pairs. In this scheme, the six revolute pairs are divided into two groups, one on each side of the base 1 and the motion platform 4, and the axes of the three revolute pairs in each group intersect at one point. The two groups of revolute pairs have two intersection points in total, and the line connecting the intersection points is the rotation axis of the equivalent motion. When the intersection points coincide, the single-degree-of-freedom spatial remote motion center mechanism is converted into a three-degree-of-freedom remote center mechanism with spatial centering.

[0044] The present invention adopts a layout of six rotating secondary axes in space to achieve single-degree-of-freedom remote rotation center motion between the base 1 and the motion platform 4; it can achieve a large range of motion around the spatial axis, and different motion boundaries can be achieved by designing the length and angle of the connecting rod; the present invention realizes an equivalent axis through the intersection of two sets of rotating axes, and achieves high rigidity outside the vertical axis plane by increasing the span of the intersection. In summary, the present invention achieves single-degree-of-freedom large-angle rotation through a symmetrical connecting rod design, and at the same time enhances rigidity through span adjustment. The present invention has a small number of mechanical parts, a simple structure, and good rigidity, which can ensure good motion accuracy.

[0045] The present invention provides a single-degree-of-freedom spatial remote motion center mechanism, which for the first time uses six spatially staggered rotation pairs to achieve motion around a spatial remote axis. It not only meets the avoidance and motion requirements of single-degree-of-freedom remote motion in applications, but also simplifies the system composition and has higher out-of-plane stiffness. It uses the principle of spatially staggered axes to expand the motion capability and can be applied to industrial manufacturing, medical robots, modifiable robots, aerospace and other fields.

[0046] The above description is only an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the scope of protection of the present invention.

Claims

1. A single-degree-of-freedom spatial remote motion center mechanism, characterized in that: It comprises a base (1), a motion platform (4), and a symmetrical connecting rod group connecting the base (1) and the motion platform (4); The symmetrical connecting rod group includes a right connecting rod group and a left connecting rod group; the right connecting rod group and the left connecting rod group each have three revolute pairs whose axes intersect at one point, and the intersection points of the axes of the three revolute pairs of the right connecting rod group and the left connecting rod group are respectively PA and PB points; The motion platform (4) can realize single-degree-of-freedom rotational motion around the line connecting point PA and point PB; When point PA coincides with point PB, the single-degree-of-freedom spatial remote motion center mechanism is converted into a spatially centered three-degree-of-freedom remote center mechanism.

2. The single-degree-of-freedom spatial remote motion center mechanism according to claim 1, characterized in that: The right connecting rod group includes a right connecting rod A (2) and a right connecting rod B (3), one end of the right connecting rod A (2) is rotatably connected to the base (1), and the secondary rotation axis is R1; the other end of the right connecting rod A (2) is rotatably connected to one end of the right connecting rod B (3), and the secondary rotation axis is R2; the other end of the right connecting rod B (3) is rotatably connected to the motion platform (4), and the secondary rotation axis is R3; R1, R2, and R3 intersect at the PA point.

3. The single-degree-of-freedom spatial remote motion center mechanism according to claim 2, characterized in that: The included angle between R1 and R2 is equal to the included angle between R3 and R2.

4. The single-degree-of-freedom spatial remote motion center mechanism according to claim 1, characterized in that: The left connecting rod group includes a left connecting rod B (5) and a left connecting rod A (6), one end of the left connecting rod A (6) is rotatably connected to the base (1), and the secondary rotation axis is L1; the other end of the left connecting rod A (6) is rotatably connected to one end of the left connecting rod B (5), and the secondary rotation axis is L2; ​​the other end of the left connecting rod B (5) is rotatably connected to the motion platform (4), and the secondary rotation axis is L3; L1, L2, and L3 intersect at the PB point.

5. The single-degree-of-freedom spatial remote motion center mechanism according to claim 4, characterized in that: The included angle between L1 and L2 is equal to the included angle between L3 and L2.

6. The single-degree-of-freedom spatial remote motion center mechanism according to claim 1, characterized in that: The base (1) is fixed, and the line connecting point PA and point PB is the axis of rotation of the equivalent motion.

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