A mechanism that moves along the instantaneous rotation axis of a spherical 4R mechanism

Abstract

The present invention belongs to the field of robotics. The present invention discloses a mechanism that moves along the instantaneous rotation axis of a spherical 4R mechanism, comprising a fixed platform, a movable platform, and three motion branches arranged between the fixed platform and the movable platform. The fixed platform is respectively provided with an eleventh rotation pair, a fourteenth rotation pair, a twenty-first rotation pair, and a twenty-fourth rotation pair. In the process of adjusting the direction of the moving motion, the movable platform moves spatially along with the rotation of the spherical 4R mechanism. When the moving platform moves faster along the instantaneous rotation axis, a larger Coriolis force is generally generated. Therefore, when the mass of the movable platform is large and the mass of the motion chain is small, the Coriolis force applied to the movable platform is almost zero, which can improve the stability of the moving platform's motion and solve the problems of low efficiency when the movable body changes its axis direction during movement and low positioning and orientation accuracy due to the impact of the Coriolis inertial force.

Description

Technical Field

[0001] The present invention relates to the field of robotics, and in particular to a mechanism that moves along the instantaneous rotation axis of a spherical 4R mechanism. Background Art

[0002] Currently, in the existing one-movement-one-rotation mechanism, the movement direction is the same as the rotation axis, and the rotation axis and the movement direction are fixed. If the rotation axis changes its axis during the movement, the direction of the movement is generally different from the rotation axis. Since the movement direction is inconsistent with the direction of the rotation axis, a Coriolis force will be generated during the movement and rotation. During high-speed movement, it will affect the smooth operation of the mechanism. To ensure the stability of its rotational movement, it is necessary to adjust the axis direction very slowly, or reduce the movement speed to minimize the Coriolis inertia force. In this case, the work efficiency is low and it cannot be applied to high-speed movement. Summary of the Invention

[0003] In order to achieve the above object, the technical solution adopted by the present invention is:

[0004] A mechanism that moves along the instantaneous rotation axis of a spherical 4R mechanism, comprising a fixed platform, a movable platform, and three motion branches arranged between the fixed platform and the movable platform, wherein the fixed platform is respectively provided with an eleventh rotating pair, a fourteenth rotating pair, a twenty-first rotating pair, and a twenty-fourth rotating pair, the fourteenth rotating pair being provided with a rotating motor, the three motion branches comprising a first branch, a second branch, and a third branch, the first branch being connected to the fixed platform via the eleventh rotating pair and the fourteenth rotating pair, the second branch being connected to the fixed platform via the twenty-first rotating pair and the twenty-fourth rotating pair, the third branch being connected to the fourth connecting rod via the thirty-first movable pair, and to the thirteenth connecting rod via the thirty-third movable pair, and the two ends of the movable platform being respectively connected to one end of the first and second branches via the seventeenth movable pair and the twenty-ninth ball pair;

[0005] The first branch chain includes a second link, a third link, a fourth link, a fifth link and a sixth link, the end of the first branch chain is connected to the moving platform through a seventeenth moving pair, the front end of the first branch chain is connected to the second link through an eleventh rotating pair, the second link is connected to the third link through a twelfth rotating pair, the third link is connected to the fourth link through a thirteenth rotating pair, the fourth link is connected to the fixed platform through the fourteenth rotating pair, the third link is connected to the fifth link through a fifteenth moving pair, the fifth link is connected to the sixth link through a sixteenth moving pair, and the sixth link is connected to the moving platform through a seventeenth moving pair;

[0006] The second branch chain includes an eighth link, a ninth link, a tenth link, an eleventh link, a twelfth link and a thirteenth link, the fixed platform is connected to the eleventh link through a twenty-first rotational pair, the eleventh link is connected to the tenth link through a twenty-fifth rotational pair, the tenth link is connected to the ninth link through a twenty-sixth rotational pair, the ninth link is connected to the thirteenth link through a twenty-seventh rotational pair, the thirteenth link is connected to the fixed platform through a twenty-fourth rotational pair, the eleventh link is connected to the twelfth link through a twenty-second rotational pair, the twelfth link is connected to the thirteenth link through a twenty-third rotational pair, the ninth link is connected to the eighth link through a twenty-eighth translational pair, and the eighth link is connected to the movable platform through a twenty-ninth ball pair;

[0007] The third branch chain includes a thirteenth link, a fourteenth link and a fifteenth link. The fourth link is connected to the fifteenth link through the thirty-first moving pair. The fifteenth link is connected to the fourteenth link through the thirty-second moving pair. The fourteenth link is connected to the thirteenth link through the thirty-third moving pair.

[0008] Furthermore, the spherical 4R mechanism composed of the eleventh rotating pair, the second connecting rod, the twelfth rotating pair, the third connecting rod, the thirteenth rotating pair, the fourth connecting rod, and the fourteenth rotating pair has the same structural parameters as the spherical 4R mechanism composed of the twenty-first rotating pair, the eleventh connecting rod, the twenty-second rotating pair, the twelfth connecting rod, the twenty-third rotating pair, the thirteenth connecting rod, and the twenty-fourth rotating pair.

[0009] Furthermore, the structural parameters of the spherical loop composed of the 21st rotational pair, the 25th rotational pair, the 26th rotational pair, the 27th rotational pair, and the 24th rotational pair are selected so as not to restrict the rotation angles of the 21st rotational pair and the 24th rotational pair in the spherical 4R loop composed of the 22nd rotational pair, the 23rd rotational pair, and the 24th rotational pair.

[0010] Furthermore, the rotation axis of the twenty-fifth rotation pair is perpendicular to the rotation axes of the twenty-first rotation pair and the twenty-second rotation pair, the rotation axis of the twenty-seventh rotation pair is perpendicular to the rotation axes of the twenty-third rotation pair and the twenty-fourth rotation pair, and the rotation axis of the twenty-sixth rotation pair is perpendicular to the rotation axes of the twenty-fifth rotation pair and the twenty-seventh rotation pair.

[0011] Furthermore, the eleventh rotation pair, the twelfth rotation pair, the thirteenth rotation pair, the fourteenth rotation pair, and the rotation axis all pass through the coordinate system point O.

[0012] Furthermore, the rotation axes of the twenty-first rotation pair, the twenty-second rotation pair, the twenty-third rotation pair, the twenty-fourth rotation pair, the twenty-fifth rotation pair, the twenty-sixth rotation pair, and the twenty-seventh rotation pair all pass through the point O2.

[0013] Furthermore, the axis of the eleventh rotating pair is parallel to the X-axis, the axis of the fourteenth rotating pair is parallel to the Y-axis, the axis of the twenty-first rotating pair is parallel to the X-axis, the axis of the twenty-fourth rotating pair is parallel to the Y-axis, the axis of the twelfth rotating pair is parallel to the XOZ plane, the axis of the thirteenth rotating pair is parallel to the YOZ plane, and the axis of the twenty-second rotating pair is parallel to the XOZ plane.

[0014] Further, the axis of the twenty-third rotating pair is parallel to the YOZ plane, the axis of the twenty-sixth rotating pair is parallel to the Z axis, the moving direction of the twenty-eighth moving pair is parallel to the Z axis, the axis of the twelfth rotating pair is parallel to the axis of the twenty-second rotating pair, the axis of the thirteenth rotating pair is parallel to the axis of the twenty-third rotating pair, the seventeenth moving pair is along the Z axis, the sixteenth moving pair is parallel to the X axis, the fifteenth moving pair is parallel to the Y axis, the twenty-eighth moving pair is parallel to the Z axis, and the rotation speed of the fourteenth rotating pair is the same as the rotation speed of the twenty-fourth rotating pair.

[0015] Furthermore, the axis of the twenty-sixth rotation pair passes through the center of the twenty-ninth spherical pair.

[0016] Furthermore, the moving direction of the fifteenth moving pair, the moving direction of the sixteenth moving pair, and the moving direction of the seventeenth moving pair are orthogonal to each other, and the moving direction of the thirty-first moving pair, the moving direction of the thirty-second moving pair, and the moving direction of the thirty-third moving pair are orthogonal to each other.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention proposes a mechanism that moves along the direction of the instantaneous rotation axis of the spherical 4R mechanism. During the process of adjusting the direction of the moving motion, the instantaneous rotation axis always coincides with its moving direction. Therefore, when the moving direction needs to be changed, the Coriolis force is zero. When the rotation speed of the one-dimensional variable axis is not high, the moving platform is accompanied by movement in space due to the rotation motion. However, at this time, the Coriolis inertia force generated by the motion is relatively small, and when there is high-speed movement along the direction of the variable axis rotation motion axis, the mechanism has the function of reducing the Coriolis inertia force of the mechanism, thereby solving the problem of low orientation accuracy and low efficiency of the mechanism when the moving direction changes under normal circumstances. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 It is a schematic diagram of the overall planar structure of the present invention.

[0021] Explanation of the accompanying symbols: 1, fixed platform; 2, second connecting rod; 3, third connecting rod; 4, fourth connecting rod; 5, fifth connecting rod; 6, sixth connecting rod; 7, movable platform; 8, eighth connecting rod; 9, ninth connecting rod; 10, tenth connecting rod; 11, eleventh connecting rod; 12, twelfth connecting rod; 13, thirteenth connecting rod; 14, fourteenth connecting rod; 15, fifteenth connecting rod;

[0022] R11, the eleventh rotational pair; R12, the twelfth rotational pair; R13, the thirteenth rotational pair; R14, the fourteenth rotational pair; P15, the fifteenth moving pair; P16, the sixteenth moving pair; P17, the seventeenth moving pair; R21, the twenty-first rotational pair; R22, the twenty-second rotational pair; R23, the twenty-third rotational pair; R24, the twenty-fourth rotational pair; R25, the twenty-fifth rotational pair; R26, the twenty-sixth rotational pair; R27, the twenty-seventh rotational pair; P28, the twenty-eighth moving pair; S29, the twenty-ninth ball pair; P31, the thirty-first moving pair; P32, the thirty-second moving pair; P33, the thirty-third moving pair. DETAILED DESCRIPTION

[0023] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined. Example

[0028] Refer to the attached Figure 1 As shown, the purpose of the present invention is to solve the problems existing in the above-mentioned technology, and provides a mechanism that moves along the instantaneous rotation axis direction of the spherical surface 4R mechanism, including a fixed platform 1, a movable platform 7 and three motion branches arranged between the fixed platform 1 and the movable platform 7, the fixed platform 1 is respectively provided with an eleventh rotation pair R11, a fourteenth rotation pair R14, a twenty-first rotation pair R21 and a twenty-fourth rotation pair R24, the fourteenth rotation pair R14 is provided with a rotating motor, the three motion branches include a first branch, a second branch and a third branch, the first branch is connected to the fixed platform 1 through the eleventh rotation pair R11 and the fourteenth rotation pair R14 respectively, the second branch is connected to the fixed platform 1 through the twenty-first rotation pair R21 and the twenty-fourth rotation pair R24 ​​respectively, the third branch is connected to the fourth connecting rod 4 through the thirty-first movable pair P31, and is connected to the thirteenth connecting rod 13 through the thirty-third movable pair P33, and the two ends of the movable platform 7 are respectively connected to one end of the first branch and the second branch through the seventeenth movable pair and the twenty-ninth ball pair S29;

[0029] The first branch chain includes a second link 2, a third link 3, a fourth link 4, a fifth link 5 and a sixth link 6. The end of the first branch chain is connected to the moving platform 7 through a seventeenth movable joint P17. The front end of the first branch chain is connected to the second link 2 through an eleventh rotational joint R11. The second link 2 is connected to the third link 3 through a twelfth rotational joint R12. The third link 3 is connected to the fourth link 4 through a thirteenth rotational joint R13. The fourth link 4 is connected to the fixed platform 1 through a fourteenth rotational joint R14. The third link 3 is connected to the fifth link 5 through a fifteenth movable joint. The fifth link 5 is connected to the sixth link 6 through a sixteenth movable joint. The sixth link 6 is connected to the moving platform 7 through a seventeenth movable joint P17.

[0030] The second branch chain includes an eighth link 8, a ninth link, a tenth link 10, an eleventh link 11, a twelfth link 12 and a thirteenth link 13. The fixed platform 1 is connected to the eleventh link 11 through a twenty-first rotational pair R21, the eleventh link 11 is connected to the tenth link 10 through a twenty-fifth rotational pair R25, the tenth link 10 is connected to the ninth link 9 through a twenty-sixth rotational pair R26, the ninth link 9 is connected to the thirteenth link 13 through a twenty-seventh rotational pair R27, the thirteenth link 13 is connected to the fixed platform 1 through a twenty-fourth rotational pair R24, the eleventh link 11 is connected to the twelfth link 12 through a twenty-second rotational pair R22, the twelfth link 12 is connected to the thirteenth link 13 through a twenty-third rotational pair R23, the ninth link 9 is connected to the eighth link 8 through a twenty-eighth translation pair P28, and the eighth link 8 is connected to the movable platform 7 through a twenty-ninth ball pair S29;

[0031] The third branch chain includes a thirteenth link 13, a fourteenth link 14 and a fifteenth link 15. The fourth link 4 is connected to the fifteenth link through a thirty-first moving pair P31, the fifteenth link 15 is connected to the fourteenth link 14 through a thirty-second moving pair P32, and the fourteenth link 14 is connected to the thirteenth link 13 through a thirty-third moving pair P33.

[0032] Furthermore, the spherical 4R mechanism composed of the eleventh rotating pair R11, the second connecting rod 2, the twelfth rotating pair R12, the third connecting rod 3, the thirteenth rotating pair R13, the fourth connecting rod 4, and the fourteenth rotating pair R14 has the same structural parameters as the spherical 4R mechanism composed of the twenty-first rotating pair R21, the eleventh connecting rod 11, the twenty-second rotating pair R22, the twelfth connecting rod 12, the twenty-third rotating pair R23, the thirteenth connecting rod 13, and the twenty-fourth rotating pair R24.

[0033] The structural parameters of the spherical loop composed of the 21st rotational pair R21, the 25th rotational pair R25, the 26th rotational pair R26, the 27th rotational pair R27, and the 24th rotational pair R24 ​​are selected so as not to restrict the rotation angle of the 21st rotational pair R21 and the 24th rotational pair R24 ​​in the spherical 4R loop composed of the 21st rotational pair R21, the 22nd rotational pair R22, the 23rd rotational pair R23, and the 24th rotational pair R24, that is, Figure 1 In the shown mechanism structure, in the spherical loop composed of the twenty-first rotational pair R21, the twenty-second rotational pair R22, the twenty-third rotational pair R23, and the twenty-fourth rotational pair R24, the rotation angle of the twenty-first rotational pair R21 and the twenty-fourth rotational pair R24 ​​is the same as the rotation angle in the spherical mechanism composed only of the twenty-first rotational pair R21, the twenty-second rotational pair R22, the twenty-third rotational pair R23, and the twenty-fourth rotational pair R24.

[0034] The rotation axis of the twenty-fifth rotation pair R25 is perpendicular to the rotation axes of the twenty-first rotation pair R21 and the twenty-second rotation pair R22, the rotation axis of the twenty-seventh rotation pair R27 is perpendicular to the rotation axes of the twenty-third rotation pair R23 and the twenty-fourth rotation pair R24, and the rotation axis of the twenty-sixth rotation pair is perpendicular to the rotation axes of the twenty-fifth rotation pair R25 and the twenty-seventh rotation pair R27.

[0035] The rotation axes of the eleventh rotation pair R11, the twelfth rotation pair R12, the thirteenth rotation pair R13, and the fourteenth rotation pair R14 all pass through the point O of the coordinate system.

[0036] The rotation axes of the twenty-first rotational pair R21, the twenty-second rotational pair R22, the twenty-third rotational pair R23, the twenty-fourth rotational pair R24, the twenty-fifth rotational pair R25, the twenty-sixth rotational pair R26 and the twenty-seventh rotational pair R27 all pass through the point O2.

[0037] The axis of the eleventh rotational pair R11 is parallel to the X-axis, the axis of the fourteenth rotational pair R14 is parallel to the Y-axis, the axis of the twenty-first rotational pair R21 is parallel to the X-axis, the axis of the twenty-fourth rotational pair R24 ​​is parallel to the Y-axis, the axis of the twelfth rotational pair R12 is parallel to the XOZ plane, the axis of the thirteenth rotational pair R13 is parallel to the YOZ plane, and the axis of the twenty-second rotational pair R22 is parallel to the XOZ plane.

[0038] The axis of the twenty-third rotation pair R23 is parallel to the YOZ plane, the axis of the twenty-sixth rotation pair R26 is parallel to the Z axis, the moving direction of the twenty-eighth mobile pair P28 is parallel to the Z axis, the axis of the twelfth rotation pair R12 is parallel to the axis of the twenty-second rotation pair R22, the axis of the thirteenth rotation pair R13 is parallel to the axis of the twenty-third rotation pair R23, the seventeenth mobile pair P17 is along the Z axis direction, the sixteenth mobile pair is parallel to the X axis, the fifteenth mobile pair is parallel to the Y axis, and the twenty-eighth mobile pair P28 is parallel to the Z axis direction.

[0039] The axis of the twenty-sixth rotational pair R26 passes through the center of the twenty-ninth spherical pair S29, and the rotation speed of the fourteenth rotational pair R14 is the same as the rotation speed of the twenty-fourth rotational pair R24.

[0040] The moving direction of the fifteenth moving pair, the moving direction of the sixteenth moving pair, and the moving direction of the seventeenth moving pair P17 are orthogonal to each other, and the moving direction of the thirty-first moving pair P31, the moving direction of the thirty-second moving pair P32, and the moving direction of the thirty-third moving pair P33 are orthogonal to each other.

[0041] The moving platform 7 has a one-dimensional variable axis rotation motion, and the one-dimensional variable axis rotation motion is accompanied by a spatial movement motion, and has a movement motion parallel to the variable axis, that is, a two-degree-of-freedom movement mode.

[0042] The axis of the one-dimensional variable axis rotation motion mode is always the same as the instantaneous rotation axis of the third connecting rod 3 in the spherical mechanism composed of the eleventh rotation pair R11, the twelfth rotation pair R12, the thirteenth rotation pair R13, and the fourteenth rotation pair R14. The direction of the one-dimensional moving motion is parallel to the moving direction of the twenty-eighth moving pair P28.

[0043] In the above two rotational movements, the one-dimensional variable axis rotational movement comes first and the one-dimensional translation movement comes second. After the one-dimensional variable axis rotational movement, the direction of the one-dimensional translation movement is changed.

[0044] A rotation drive is provided at the fourteenth rotation pair R14, and a movement drive is provided at the twenty-eighth movement pair P28.

[0045] The present invention proposes a mechanism that moves along the instantaneous rotation axis of the spherical 4R mechanism. Each drive controls an independent movement of the moving platform 7, making it easier to control the mechanism. The one-dimensional movement and one-dimensional variable axis rotation of the mechanism are completely decoupled.

[0046] Generally, when a mobile motion requires adjusting its direction during high-speed motion, a large Coriolis force is generated, affecting motion stability and hindering the precise positioning and orientation of one-dimensional motion and rotation. To ensure motion stability, the one-dimensional motion must be adjusted very slowly or at a reduced speed, which is inefficient and unsuitable for high-speed motion.

[0047] The present invention proposes a mechanism that moves along the direction of the instantaneous rotation axis of the spherical 4R mechanism. During the process of adjusting the direction of the moving motion, the instantaneous rotation axis always coincides with its moving direction. Therefore, when the moving direction needs to be changed, the Coriolis force is zero. When the one-dimensional variable axis rotation speed is not high, the moving platform 7 is accompanied by movement in space due to the rotation motion. However, at this time, the Coriolis inertia force generated by the motion is small, and when there is high-speed movement along the direction of the variable axis rotation motion axis, the mechanism has the function of reducing the Coriolis inertia force of the mechanism, thereby solving the problem that, under normal circumstances, the mechanism orientation accuracy is not high and the efficiency is low when the moving direction changes.

[0048] The above is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A mechanism that moves along the instantaneous rotation axis of a spherical 4R mechanism, characterized in that: It includes a fixed platform, a movable platform and three motion branches arranged between the fixed platform and the movable platform, the fixed platform is respectively provided with an eleventh rotating pair, a fourteenth rotating pair, a twenty-first rotating pair and a twenty-fourth rotating pair, the fourteenth rotating pair is provided with a rotating motor, the three motion branches include a first branch chain, a second branch chain and a third branch chain, the first branch chain is respectively connected to the fixed platform through the eleventh rotating pair and the fourteenth rotating pair, the second branch chain is respectively connected to the fixed platform through the twenty-first rotating pair and the twenty-fourth rotating pair, the third branch chain is connected to the fourth connecting rod through the thirty-first movable pair, and is connected to the thirteenth connecting rod through the thirty-third movable pair, and the two ends of the movable platform are respectively connected to one end of the first branch chain and the second branch chain through the seventeenth movable pair and the twenty-ninth ball pair; The first branch chain includes a second link, a third link, a fourth link, a fifth link and a sixth link, the end of the first branch chain is connected to the moving platform through a seventeenth moving pair, the front end of the first branch chain is connected to the second link through an eleventh rotating pair, the second link is connected to the third link through a twelfth rotating pair, the third link is connected to the fourth link through a thirteenth rotating pair, the fourth link is connected to the fixed platform through the fourteenth rotating pair, the third link is connected to the fifth link through a fifteenth moving pair, the fifth link is connected to the sixth link through a sixteenth moving pair, and the sixth link is connected to the moving platform through a seventeenth moving pair; The second branch chain includes an eighth link, a ninth link, a tenth link, an eleventh link, a twelfth link and a thirteenth link, the fixed platform is connected to the eleventh link through a twenty-first rotational pair, the eleventh link is connected to the tenth link through a twenty-fifth rotational pair, the tenth link is connected to the ninth link through a twenty-sixth rotational pair, the ninth link is connected to the thirteenth link through a twenty-seventh rotational pair, the thirteenth link is connected to the fixed platform through a twenty-fourth rotational pair, the eleventh link is connected to the twelfth link through a twenty-second rotational pair, the twelfth link is connected to the thirteenth link through a twenty-third rotational pair, the ninth link is connected to the eighth link through a twenty-eighth translational pair, and the eighth link is connected to the movable platform through a twenty-ninth ball pair; The third branch chain includes a thirteenth link, a fourteenth link and a fifteenth link. The fourth link is connected to the fifteenth link through the thirty-first moving pair. The fifteenth link is connected to the fourteenth link through the thirty-second moving pair. The fourteenth link is connected to the thirteenth link through the thirty-third moving pair.

2. A mechanism that moves along the instantaneous rotation axis of a spherical 4R mechanism according to claim 1, characterized in that: The spherical 4R mechanism composed of the eleventh rotating pair, the second connecting rod, the twelfth rotating pair, the third connecting rod, the thirteenth rotating pair, the fourth connecting rod, and the fourteenth rotating pair has the same structural parameters as the spherical 4R mechanism composed of the twenty-first rotating pair, the eleventh connecting rod, the twenty-second rotating pair, the twelfth connecting rod, the twenty-third rotating pair, the thirteenth connecting rod, and the twenty-fourth rotating pair.

3. A mechanism that moves along the instantaneous rotation axis of a spherical 4R mechanism according to claim 2, characterized in that: The structural parameters of the spherical loop composed of the 21st rotational pair, the 25th rotational pair, the 26th rotational pair, the 27th rotational pair and the 24th rotational pair are selected so as not to restrict the rotation angles of the 21st rotational pair and the 24th rotational pair in the spherical 4R loop composed of the 22nd rotational pair, the 23rd rotational pair and the 24th rotational pair.

4. A mechanism that moves along the instantaneous rotation axis of a spherical 4R mechanism according to claim 3, characterized in that: The rotation axis of the 25th rotational pair is perpendicular to the rotation axes of the 21st rotational pair and the 22nd rotational pair, the rotation axis of the 27th rotational pair is perpendicular to the rotation axes of the 23rd rotational pair and the 24th rotational pair, and the rotation axis of the 26th rotational pair is perpendicular to the rotation axes of the 25th rotational pair and the 27th rotational pair.

5. A mechanism that moves along the instantaneous rotation axis of a spherical 4R mechanism according to claim 4, characterized in that: The rotation axes of the eleventh rotation pair, the twelfth rotation pair, the thirteenth rotation pair, the fourteenth rotation pair all pass through the point O of the coordinate system.

6. A mechanism that moves along the instantaneous rotation axis of a spherical 4R mechanism according to claim 5, characterized in that: The rotation axes of the 21st rotation pair, the 22nd rotation pair, the 23rd rotation pair, the 24th rotation pair, the 25th rotation pair, the 26th rotation pair, and the 27th rotation pair all pass through the point O2.

7. A mechanism that moves along the instantaneous rotation axis of a spherical 4R mechanism according to claim 6, characterized in that: The axis of the eleventh rotation pair is parallel to the X-axis, the axis of the fourteenth rotation pair is parallel to the Y-axis, the axis of the twenty-first rotation pair is parallel to the X-axis, the axis of the twenty-fourth rotation pair is parallel to the Y-axis, the axis of the twelfth rotation pair is parallel to the XOZ plane, the axis of the thirteenth rotation pair is parallel to the YOZ plane, and the axis of the twenty-second rotation pair is parallel to the XOZ plane.

8. The mechanism for moving along the instantaneous rotation axis of the spherical 4R mechanism according to claim 7, characterized in that: The axis of the twenty-third rotating pair is parallel to the YOZ plane, the axis of the twenty-sixth rotating pair is parallel to the Z axis, the moving direction of the twenty-eighth moving pair is parallel to the Z axis, the axis of the twelfth rotating pair is parallel to the axis of the twenty-second rotating pair, the axis of the thirteenth rotating pair is parallel to the axis of the twenty-third rotating pair, the seventeenth moving pair is along the Z axis, the sixteenth moving pair is parallel to the X axis, the fifteenth moving pair is parallel to the Y axis, and the twenty-eighth moving pair is parallel to the Z axis.

9. The mechanism for moving along the instantaneous rotation axis of the spherical 4R mechanism according to claim 8, characterized in that: The axis of the twenty-sixth rotational pair passes through the center of the twenty-ninth spherical pair, and the rotation speed of the fourteenth rotational pair is the same as the rotation speed of the twenty-fourth rotational pair.

10. The mechanism for moving along the instantaneous rotation axis of the spherical 4R mechanism according to claim 9, characterized in that: The moving direction of the fifteenth moving pair, the moving direction of the sixteenth moving pair, and the moving direction of the seventeenth moving pair are orthogonal to each other, and the moving direction of the thirty-first moving pair, the moving direction of the thirty-second moving pair, and the moving direction of the thirty-third moving pair are orthogonal to each other.

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