A fully decoupled parallel mechanism with variable rotation axis mode and working method thereof

Abstract

The present invention discloses a fully decoupled parallel mechanism with a variable axis mode and a working method thereof, belonging to the field of robot technology. It includes a fixed platform, a moving platform, and a first branch chain, a second branch chain, a third branch chain, and a fourth branch chain arranged between the fixed platform and the moving platform. Each drive pair controls an independent movement of the moving platform, and it is easy to realize the control of the mechanism. When the multi-mode mechanism is working, it may be necessary to change the motion mode. The fully decoupled mechanism structure makes it easier to implement the motion mode change, which is convenient for the change of the mechanism motion mode, and improves the practicality of the multi-mode mechanism. In both motion modes, the mechanism has the characteristics of complete decoupling, which improves the controllability of completing different work tasks. When the moving platform needs to adjust a specific spatial posture during spatial movement, such as in scenes such as a vibrating screen, a motion simulator, an assembly robot, or a spraying robot, when the working hand posture needs to be adjusted, it has good applicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of robots, and in particular relates to a fully decoupled parallel mechanism with a variable rotation axis mode and a working method thereof. Background Art

[0002] Parallel robots have the characteristics of high stiffness, strong load capacity, small accumulated error, and good dynamic performance. Parallel robots with 3 movement and 1 rotation motion modes are more common in application scenarios that require spatial movement and posture adjustment. In some scenarios where complex changes are required in spatial working postures, the end of the parallel robot needs to rotate the variable axis. The input and output of the parallel mechanism generally present a highly nonlinear relationship, so its kinematic and dynamic calculations are more complex and difficult to control.

[0003] The existing fully decoupled mechanism configuration with 3T1R motion mode is very rare, and the relationship between input and output is highly nonlinear, making it difficult to control. Summary of the invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide a fully decoupled parallel mechanism with a variable axis mode and a working method thereof. The motion mode change is easy to control and has high practicality. In both motion modes, the mechanism has the characteristics of complete decoupling, which improves the controllability of completing different work tasks.

[0005] The present invention is achieved through the following technical solutions:

[0006] The present invention discloses a fully decoupled parallel mechanism with a variable rotation axis mode, comprising a fixed platform, a movable platform, and a first branch chain, a second branch chain, a third branch chain and a fourth branch chain arranged between the fixed platform and the movable platform;

[0007] The first branch chain includes an eleventh moving pair, a second connecting rod, a twelfth moving pair, a third connecting rod, a thirteenth moving pair, a fourth connecting rod, a fourteenth rotating pair, a fifth connecting rod and a fifteenth rotating pair connected in sequence; the eleventh moving pair is connected to the fixed platform, and the fifteenth rotating pair is connected to the moving platform;

[0008] The second branch chain includes a 21st rotating pair, a 6th connecting rod, a 22nd rotating pair, a 7th connecting rod, a 23rd rotating pair, an 8th connecting rod and a 24th rotating pair connected in sequence; the 7th connecting rod is connected in sequence to a 25th moving pair, a 9th connecting rod, a 26th moving pair, a 10th connecting rod and a 27th moving pair; the 21st rotating pair and the 24th rotating pair are respectively connected to the fixed platform, and the 27th moving pair is connected to the moving platform;

[0009] The third branch chain includes a thirty-first moving pair, an eleventh connecting rod, a thirty-second moving pair, a twelfth connecting rod, a thirty-third moving pair, a thirteenth connecting rod, a thirty-fourth rotating pair, a fourteenth connecting rod and a thirty-fifth rotating pair which are connected in sequence; the thirty-first moving pair is connected to the fixed platform, and the thirty-fifth rotating pair is connected to the moving platform;

[0010] The fourth branch chain includes a 41st moving pair, a 15th connecting rod, a 42nd moving pair, a 16th connecting rod, a 43rd moving pair, a 17th connecting rod, a 44th rotating pair, an 18th connecting rod and a 45th rotating pair which are connected in sequence; the 41st moving pair is connected to the fixed platform, and the 45th rotating pair is connected to the moving platform.

[0011] Preferably, the eleventh moving pair, the twenty-fifth moving pair, the thirty-second moving pair and the forty-second moving pair are parallel to the Z-axis direction.

[0012] Preferably, the twelfth moving pair, the thirty-first moving pair and the forty-third moving pair are parallel to the X-axis direction.

[0013] Preferably, the thirteenth moving pair, the thirty-third moving pair and the forty-first moving pair are parallel to the Y-axis direction.

[0014] Preferably, the fourteenth rotation pair, the twenty-first rotation pair and the thirty-fourth rotation pair are parallel to the Y-axis direction.

[0015] Preferably, the twenty-fourth rotation pair and the forty-fourth rotation pair are parallel to the X-axis direction.

[0016] Preferably, the axes of the twenty-first rotation pair, the twenty-second rotation pair, the twenty-third rotation pair and the twenty-fourth rotation pair intersect at one point; the angle between the axis of the twenty-first rotation pair and the twenty-second rotation pair is 45°, the angle between the axis of the twenty-second rotation pair and the twenty-third rotation pair is 90°, the angle between the axis of the twenty-third rotation pair and the twenty-fourth rotation pair is 45°, and the angle between the axis of the twenty-fourth rotation pair and the twenty-first rotation pair is 90°.

[0017] Preferably, the axes of the fifteenth rotating pair and the thirty-fifth rotating pair are parallel to the axis of the twenty-second rotating pair; the forty-fifth rotating pair is parallel to the axis of the twenty-third rotating pair; the axes of the fourteenth rotating pair, the fifteenth rotating pair, the thirty-fourth rotating pair, the thirty-fifth rotating pair, the forty-fourth rotating pair and the forty-fifth rotating pair intersect at one point; the plane where the axes of the fourteenth rotating pair, the fifteenth rotating pair, the thirty-fourth rotating pair, the thirty-fifth rotating pair, the forty-fourth rotating pair and the forty-fifth rotating pair lie coincides with the XOY plane; the plane where the axes of the twenty-first rotating pair, the twenty-second rotating pair, the twenty-third rotating pair and the twenty-fourth rotating pair lie is parallel to the XOY plane; the moving direction of the twenty-seventh moving pair is parallel to the axis of the forty-fifth rotating pair; the moving direction of the twenty-seventh moving pair is perpendicular to the moving direction of the twenty-sixth moving pair; the moving direction of the twenty-seventh moving pair and the moving direction of the twenty-sixth moving pair are parallel to the XOY plane.

[0018] Preferably, the eleventh moving pair, the twenty-first moving pair, the thirty-first moving pair, the forty-first rotating pair and the forty-fourth rotating pair are all provided with drive motors; and the twenty-fourth rotating pair is provided with an auxiliary drive motor.

[0019] The working method of the above-mentioned fully decoupled parallel mechanism with a variable rotation axis mode disclosed in the present invention comprises:

[0020] Lock the eleventh moving pair, the thirty-first moving pair and the forty-first moving pair, and drive the twenty-first rotating pair and the twenty-fourth rotating pair to rotate;

[0021] The eleventh moving pair is controlled to move the movable platform along the Z axis; the thirty-first moving pair is controlled to move the movable platform along the X axis; the forty-first moving pair is controlled to move the movable platform along the Y axis; the twenty-first rotation pair is controlled to make the movable platform perform a one-dimensional rotation with the rotation axis changing in space.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects:

[0023] The present invention discloses a fully decoupled parallel mechanism with a variable rotation axis mode, in which each driving pair controls an independent movement of a moving platform, and the control of the mechanism is easy to achieve. When the multi-mode mechanism is working, it may be necessary to change the motion mode. The fully decoupled mechanism structure makes it easier to implement the motion mode change, which is convenient for the change of the mechanism motion mode, improves the practicality of the multi-mode mechanism, and in both motion modes, the mechanism has the characteristics of complete decoupling, which improves the controllability of completing different work tasks. The instantaneous rotation axis of the moving platform changes continuously during the working process, and can pass through some postures that cannot be reached by fixed-axis rotation, so that this type of mechanism can complete some complex work tasks. When the moving platform needs to adjust a series of specific spatial postures during spatial movement, such as in scenes such as vibrating screens, motion simulators, assembly robots or spray robots, when the working hand posture needs to be adjusted, it has good applicability.

[0024] The working method of the fully decoupled parallel mechanism with variable axis mode disclosed in the present invention, in the general configuration of the mechanism, controls the driving pair placed on the fixed platform to independently control the corresponding independent movement of the moving platform. In the process of changing the two variable axis motion modes, it is necessary to add an auxiliary driving pair to realize the change of the two variable axis motion modes. The motion mode change is easy to control and has high practicality. In different motion modes, the mechanism has the characteristics of complete decoupling, which improves the controllability of completing different work tasks. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the system of the present invention;

[0026] Figure 2 It is a schematic diagram of the first configuration of the system of the present invention;

[0027] Figure 3 This is a schematic diagram of the second configuration of the system of the present invention.

[0028] In the figure: 1-fixed platform, 2-second connecting rod, 3-third connecting rod, 4-fourth connecting rod, 5-fifth connecting rod, 6-sixth connecting rod, 7-seventh connecting rod, 8-eighth connecting rod, 9-moving platform, 10-tenth connecting rod, 11-eleventh connecting rod, 12-twelfth connecting rod, 13-thirteenth connecting rod, 14-fourteenth connecting rod, 15-fifteenth connecting rod, 16-sixteenth connecting rod, 17-seventeenth connecting rod, 18-eighteenth connecting rod, 19-moving platform, P11-eleventh moving pair, P12-twelfth moving pair, P13-thirteenth moving pair, R14-fourteenth rotation pair, R15-fifteenth rotation pair , R21- the twenty-first rotating pair, R22- the twenty-second rotating pair, R23- the twenty-third rotating pair, R24- the twenty-fourth rotating pair, P25- the twenty-fifth moving pair, P26- the twenty-sixth moving pair, P27- the twenty-seventh moving pair, P31- the thirty-first moving pair, P32- the thirty-second moving pair, P33- the thirty-third moving pair, R34- the thirty-fourth rotating pair, R35- the thirty-fifth rotating pair, P41- the forty-first moving pair, P42- the forty-second moving pair, P43- the forty-third moving pair, R44- the forty-fourth rotating pair, R45- the forty-fifth rotating pair. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, the contents of which are intended to explain the present invention rather than to limit it:

[0030] like Figure 1 , which is a fully decoupled parallel mechanism with a variable axis mode of the present invention, includes a fixed platform 1, a moving platform 19, and four motion branches arranged between the fixed platform 1 and the moving platform 19.

[0031] The fixed platform 1 is respectively provided with an eleventh moving pair P11 , a thirty-first moving pair P31 , a twenty-first rotation pair R21 , a twenty-fourth rotation pair R24 ​​and a forty-first moving pair P41 .

[0032] The eleventh movable pair P11, the thirty-first movable pair P31, the twenty-first rotational pair R21 and the forty-first movable pair P41 are all provided with driving motors; the twenty-fourth rotational pair R24 ​​is provided with an auxiliary driving motor.

[0033] The moving branch chain includes a first branch chain, a second branch chain, a third branch chain and a fourth branch chain. One end of the first branch chain, one end of the second branch chain, one end of the third branch chain and one end of the fourth branch chain are respectively connected to the fixed platform 1 through the eleventh moving pair P11, the twenty-first rotation pair R21, the twenty-fourth rotation pair R24, the thirty-first moving pair P31 and the forty-first moving pair P41.

[0034] The other end of the first branch chain, the other end of the second branch chain, the other end of the third branch chain and the other end of the fourth branch chain are respectively connected to the moving platform 19 through the fifteenth rotation pair R15, the twenty-seventh movable pair P27, the thirty-fifth rotation pair R35 and the forty-fifth rotation pair R45.

[0035] The first branch chain is composed of the eleventh movable pair P11, which is connected in sequence to the second link 2, the twelfth movable pair P12, the third link 3, the thirteenth movable pair P13, the fourth link 4, the fourteenth rotation pair R14, the fifth link 5 and the fifteenth rotation pair R15.

[0036] The second branch chain is composed of the 21st rotation pair R21, which is connected in sequence to the 6th link 6, the 22nd rotation pair R22, the 7th link 7, the 23rd rotation pair R23, the 8th link 8 and the 24th rotation pair R24. The 7th link 7 is also connected in sequence to the 25th mobile pair P25, the 9th link 9, the 26th mobile pair P26, the 10th link 10 and the 27th mobile pair P27.

[0037] The third branch chain consists of the thirty-first movable pair P31, which sequentially connects the eleventh connecting rod 11, the thirty-second movable pair P32, the twelfth connecting rod 12, the thirty-third movable pair P33, the thirteenth connecting rod 13, the thirty-fourth rotational pair R34, the fourteenth connecting rod 14 and the thirty-fifth rotational pair R35.

[0038] The fourth branch chain is composed of the 41st movable pair P41, which is connected in sequence to the 15th connecting rod 15, the 42nd movable pair P42, the 16th connecting rod 16, the 43rd movable pair P43, the 17th connecting rod 17, the 44th rotational pair R44, the 18th connecting rod 18 and the 45th rotational pair R45.

[0039] Figure 1 In the shown mechanism configuration, the eleventh moving pair P11, the twenty-fifth moving pair P25, the thirty-second moving pair P32, and the forty-second moving pair P42 are parallel to the Z-axis direction.

[0040] Figure 1 In the shown mechanism configuration, the twelfth mobile pair P12, the thirty-first mobile pair P31, and the forty-third mobile pair P43 are parallel to the X-axis direction.

[0041] Figure 1 In the shown mechanism configuration, the thirteenth mobile pair P13, the thirty-third mobile pair P33, and the forty-first mobile pair P41 are parallel to the Y-axis direction.

[0042] Figure 1 In the shown mechanism configuration, the fourteenth rotation pair R14, the twenty-first rotation pair R21, and the thirty-fourth rotation pair R34 are parallel to the Y-axis direction.

[0043] Figure 1 In the shown mechanism configuration, the twenty-fourth rotation pair R24 ​​and the forty-fourth rotation pair R44 are parallel to the X-axis direction.

[0044] Figure 1 Under the shown mechanism configuration, the axes of the twenty-first rotation pair R21, the twenty-second rotation pair R22, the twenty-third rotation pair R23, and the twenty-fourth rotation pair R24 ​​intersect at point o; the angle between the axes of the twenty-first rotation pair R21 and the twenty-second rotation pair R22 is 45°, the angle between the axes of the twenty-second rotation pair R22 and the twenty-third rotation pair R23 is 90°, the angle between the axes of the twenty-third rotation pair R23 and the twenty-fourth rotation pair R24 ​​is 45°, and the angle between the axes of the twenty-fourth rotation pair R24 ​​and the twenty-first rotation pair R21 is 90°.

[0045] Figure 1 In the shown mechanism configuration, the axes of the fifteenth rotation pair R15 and the thirty-fifth rotation pair R35 are parallel to the axis of the twenty-second rotation pair R22.

[0046] Figure 1 In the shown mechanism configuration, the axis of the forty-fifth rotation pair R45 is parallel to the axis of the twenty-third rotation pair R23.

[0047] Figure 1 In the shown mechanism configuration, the axis of the fourteenth rotation pair R14, the axis of the fifteenth rotation pair R15, the axis of the thirty-fourth rotation pair R34, the axis of the thirty-fifth rotation pair R35, the axis of the forty-fourth rotation pair R44 and the axis of the forty-fifth rotation pair R45 intersect at point O.

[0048] Figure 1 In the shown mechanism configuration, the planes where the axes of the fourteenth rotation pair R14, the fifteenth rotation pair R15, the thirty-fourth rotation pair R34, the thirty-fifth rotation pair R35, the forty-fourth rotation pair R44 and the forty-fifth rotation pair R45 are located coincide with the XOY plane.

[0049] Figure 1 In the shown mechanism configuration, the axis of the twenty-first rotation pair R21, the axis of the twenty-second rotation pair R22, the axis of the twenty-third rotation pair R23, and the axis of the twenty-fourth rotation pair R24 ​​are located in a plane parallel to the XOY plane.

[0050] Figure 1 In the shown mechanism configuration, the moving direction of the twenty-seventh moving pair P27 is parallel to the axis of the forty-fifth rotation pair R45. The moving direction of the twenty-seventh moving pair P27 is perpendicular to the moving direction of the twenty-sixth moving pair P26. The moving directions of the twenty-seventh moving pair P27 and the twenty-sixth moving pair P26 are parallel to the XOY plane.

[0051] Figure 1In the shown mechanism configuration, the moving platform has two modes of motion: three-dimensional movement in XYZ space and one-dimensional rotation with axis direction change. These two modes of motion are Figure 1 The configuration shown is instantaneous.

[0052] exist Figure 1 In the shown mechanism configuration, the eleventh moving pair P11 is locked, the thirty-first moving pair P31 and the forty-first moving pair P41 are locked, the twenty-first rotation pair R21 is driven to rotate, and the twenty-fourth rotation pair R24 ​​is driven to rotate, so that the mechanism moves to Figure 2 The mechanism configuration shown in the figure has the first three-dimensional movement and one-dimensional variable axis rotation motion mode.

[0053] exist Figure 2 In the shown mechanism configuration, the eleventh moving pair P11 can be controlled to move the moving platform 19 along the Z axis. The thirty-first moving pair P31 can be controlled to move the moving platform 19 along the X axis. The forty-first moving pair P41 can be controlled to move the moving platform 19 along the Y axis. The twenty-first rotation pair R21 can be controlled to make the moving platform 19 perform a one-dimensional rotation with the rotation axis changing in space. Figure 2 In the shown mechanism configuration, the three-dimensional movement and one-dimensional rotation of the moving platform 19 are both driven by a driving motor installed on the fixed platform 1 to drive the above-mentioned kinematic pair, thereby realizing one-dimensional movement of the moving platform 19 controlled by one drive. Figure 2 In the shown mechanism configuration, the mechanism has a first completely decoupled variable axis 3 movement 1 rotation motion mode.

[0054] exist Figure 1 In the shown mechanism configuration, the eleventh moving pair P11 is locked, the thirty-first moving pair P31 and the forty-first moving pair P41 are locked, the twenty-first rotation pair R21 is driven to rotate, and the twenty-fourth rotation pair R24 ​​is driven to rotate, so that the mechanism moves to Figure 3 The mechanism configuration shown in the figure has a second three-dimensional movement and one-dimensional variable axis rotation motion mode.

[0055] exist Figure 3 In the shown mechanism configuration, the eleventh moving pair P11 can be controlled to move the moving platform 19 along the Z axis. The thirty-first moving pair P31 can be controlled to move the moving platform 19 along the X axis. The forty-first moving pair P41 can be controlled to move the moving platform 19 along the Y axis. The twenty-first rotation pair R21 can be controlled to make the moving platform 19 perform a one-dimensional rotation with the rotation axis changing in space. Figure 3 In the shown mechanism configuration, the three-dimensional movement and one-dimensional rotation of the moving platform 19 are both driven by a driving motor installed on the fixed platform 1 to drive the above-mentioned kinematic pair, thereby realizing one-dimensional movement of the moving platform 19 controlled by one drive. Figure 3In the shown mechanism configuration, the mechanism has a second completely decoupled variable axis 3 movement 1 rotation motion mode.

[0056] The above is only part of the embodiments of the present invention. Although some terms are used in the present invention, the possibility of using other terms is not excluded. The use of these terms is only for the convenience of describing and explaining the essence of the present invention. It is contrary to the spirit of the present invention to interpret them as any additional restrictions. The above is only to further illustrate the content of the present invention with examples for easier understanding, but it does not mean that the embodiments of the present invention are limited to this. Any technical extension or re-creation made according to the present invention is protected by the present invention.

Claims

1. A fully decoupled parallel mechanism with a variable axis mode, characterized in that: It comprises a fixed platform (1), a movable platform (19), and a first branch chain, a second branch chain, a third branch chain and a fourth branch chain arranged between the fixed platform (1) and the movable platform (19); The first branch chain comprises an eleventh movable pair (P11), a second connecting rod (2), a twelfth movable pair (P12), a third connecting rod (3), a thirteenth movable pair (P13), a fourth connecting rod (4), a fourteenth rotating pair (R14), a fifth connecting rod (5) and a fifteenth rotating pair (R15) which are connected in sequence; the eleventh movable pair (P11) is connected to the fixed platform (1), and the fifteenth rotating pair (R15) is connected to the movable platform (19); The second branch chain comprises a twenty-first rotation pair (R21), a sixth connecting rod (6), a twenty-second rotation pair (R22), a seventh connecting rod (7), a twenty-third rotation pair (R23), an eighth connecting rod (8) and a twenty-fourth rotation pair (R24) which are connected in sequence; at the same time, the seventh connecting rod (7) is connected in sequence to a twenty-fifth mobile pair (P25), a ninth connecting rod (9), a twenty-sixth mobile pair (P26), a tenth connecting rod (10) and a twenty-seventh mobile pair (P27); the twenty-first rotation pair (R21) and the twenty-fourth rotation pair (R24) are respectively connected to the fixed platform (1), and the twenty-seventh mobile pair (P27) is connected to the movable platform (19); The third branch chain comprises a thirty-first moving pair (P31), an eleventh connecting rod (11), a thirty-second moving pair (P32), a twelfth connecting rod (12), a thirty-third moving pair (P33), a thirteenth connecting rod (13), a thirty-fourth rotating pair (R34), a fourteenth connecting rod (14) and a thirty-fifth rotating pair (R35) which are connected in sequence; the thirty-first moving pair (P31) is connected to the fixed platform (1), and the thirty-fifth rotating pair (R35) is connected to the moving platform (19); The fourth branch chain comprises a forty-first moving pair (P41), a fifteenth connecting rod (15), a forty-second moving pair (P42), a sixteenth connecting rod (16), a forty-third moving pair (P43), a seventeenth connecting rod (17), a forty-fourth rotating pair (R44), an eighteenth connecting rod (18) and a forty-fifth rotating pair (R45) which are connected in sequence; the forty-first moving pair (P41) is connected to the fixed platform (1), and the forty-fifth rotating pair (R45) is connected to the moving platform (19).

2. The fully decoupled parallel mechanism with a variable rotation axis mode according to claim 1, characterized in that: The eleventh moving pair (P11), the twenty-fifth moving pair (P25), the thirty-second moving pair (P32) and the forty-second moving pair (P42) are parallel to the Z-axis direction.

3. The fully decoupled parallel mechanism with a variable rotation axis mode according to claim 1, characterized in that: The twelfth movable pair (P12), the thirty-first movable pair (P31) and the forty-third movable pair (P43) are parallel to the X-axis direction.

4. The fully decoupled parallel mechanism with a variable rotation axis mode according to claim 1, characterized in that: The thirteenth movable pair (P13), the thirty-third movable pair (P33) and the forty-first movable pair (P41) are parallel to the Y-axis direction.

5. The fully decoupled parallel mechanism with a variable rotation axis mode according to claim 1, characterized in that: The fourteenth rotation pair (R14), the twenty-first rotation pair (R21) and the thirty-fourth rotation pair (R34) are parallel to the Y-axis direction.

6. The fully decoupled parallel mechanism with a variable rotation axis mode according to claim 1, characterized in that: The twenty-fourth rotation pair (R24) and the forty-fourth rotation pair (R44) are parallel to the X-axis direction.

7. The fully decoupled parallel mechanism with a variable rotation axis mode according to claim 1, characterized in that: The axes 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) intersect at one point; the angle between the axes of the twenty-first rotational pair (R21) and the twenty-second rotational pair (R22) is 45°, the angle between the axes of the twenty-second rotational pair (R22) and the twenty-third rotational pair (R23) is 90°, the angle between the axes of the twenty-third rotational pair (R23) and the twenty-fourth rotational pair (R24) is 45°, and the angle between the axes of the twenty-fourth rotational pair (R24) and the twenty-first rotational pair (R21) is 90°.

8. The fully decoupled parallel mechanism with a variable rotation axis mode according to claim 1, characterized in that: The axes of the fifteenth rotation pair (R15) and the thirty-fifth rotation pair (R35) are parallel to the axis of the twenty-second rotation pair (R22); the forty-fifth rotation pair (R45) is parallel to the axis of the twenty-third rotation pair (R23); the axes of the fourteenth rotation pair (R14), the fifteenth rotation pair (R15), the thirty-fourth rotation pair (R34), the thirty-fifth rotation pair (R35), the forty-fourth rotation pair (R44) and the forty-fifth rotation pair (R45) intersect at one point; the fourteenth rotation pair (R14), the fifteenth rotation pair (R15), the thirty-fourth rotation pair (R34), the thirty-fifth rotation pair (R35), the forty-fourth rotation pair (R44) and the forty-fifth rotation pair (R45) intersect at one point The plane where the axes of the twenty-first rotation pair (R21), the twenty-second rotation pair (R22), the twenty-third rotation pair (R23) and the twenty-fourth rotation pair (R24) are located coincides with the XOY plane; the plane where the axes of the twenty-seventh rotation pair (P27) are located are parallel to the XOY plane; the moving direction of the twenty-seventh rotation pair (P27) is parallel to the axis of the forty-fifth rotation pair (R45); the moving direction of the twenty-seventh rotation pair (P27) is perpendicular to the moving direction of the twenty-sixth rotation pair (P26); the moving direction of the twenty-seventh rotation pair (P27) and the moving direction of the twenty-sixth rotation pair (P26) are parallel to the XOY plane.

9. The fully decoupled parallel mechanism with a variable rotation axis mode according to claim 1, characterized in that: The eleventh movable pair (P11), the twenty-first movable pair (P21), the thirty-first movable pair (P31), the forty-first rotating pair (R41) and the forty-fourth rotating pair (R44) are all provided with driving motors; the twenty-fourth rotating pair (R24) is provided with an auxiliary driving motor.

10. The working method of the fully decoupled parallel mechanism with a variable rotation axis mode according to any one of claims 1 to 9, characterized in that: include: Locking the eleventh movable pair (P11), the thirty-first movable pair (P31) and the forty-first movable pair (P41), driving the twenty-first rotation pair (R21) and the twenty-fourth rotation pair (R24) to rotate; The eleventh movable pair (P11) is controlled to move the movable platform (19) along the Z axis; the thirty-first movable pair (P31) is controlled to move the movable platform (19) along the X axis; the forty-first movable pair (P41) is controlled to move the movable platform (19) along the Y axis; and the twenty-first rotation pair (R21) is controlled to make the movable platform (19) perform a one-dimensional rotation with the rotation axis changing in space.

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