A three-degree-of-freedom parallel joint mechanism

Abstract

The present invention relates to a three-degree-of-freedom parallel joint mechanism, comprising a fixing device, a cross hinge structure, a Z-axis driver, a Y-axis driver and an X-axis driver, wherein the output axes of the Z-axis driver, the Y-axis driver and the X-axis driver are orthogonal to each other, and the relative positions of the output axes of the Z-axis driver, the Y-axis driver and the X-axis driver are relatively fixed by the fixing device, and the output axis of the X-axis driver can drive the cross hinge structure to rotate continuously, and the cross hinge output axis is a moving platform. The three-degree-of-freedom parallel joint mechanism of the present invention can obtain a larger rotation angle range, especially wherein the rotation angle of the rotation freedom along the X-axis can be infinite, and the rotation angle range around the Y-axis and the Z-axis is ±90 degrees, and is only related to the rotation angle of the Y-axis driver and the Z-axis driver, respectively, and the rotation in each direction can be performed separately, or in any two directions at the same time, or in three directions at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-degree-of-freedom joints, and in particular to a three-degree-of-freedom parallel joint mechanism. Background Art

[0002] A three-degree-of-freedom joint mechanism refers to a joint mechanism with three rotational degrees of freedom. It is widely used in a large number of applications such as robots, five-axis machining centers, radars or camera posture adjusters, etc. Compared with traditional serial joint mechanisms, parallel joint mechanisms have the advantages of high precision and strong load-bearing capacity. The existing three-degree-of-freedom parallel joint mechanisms all have three branches, and the moving platform has the freedom to rotate around three axes. Compared with two-degree-of-freedom parallel joint mechanisms, three-degree-of-freedom parallel joint mechanisms are more complex, and there are relatively few configurations that can be successfully applied, but their application fields are very broad. Figure 1 As shown in the figure, the Agile eye parallel mechanism with three rotational degrees of freedom proposed by Canadian scholar Gosselin can realize fast and flexible rotation of the camera fixed on the moving platform. Although the Agile eye mechanism is relatively flexible, it has a complex structure, a large number of parts and is difficult to process, and it is not easy to reduce the volume; the rotation angle of each rotational degree of freedom is relatively small. If you want to make the moving platform rotate at a larger angle, you need to make the three axes linked, so it is difficult to meet the more demanding application environment. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects of the prior art and provide a three-degree-of-freedom parallel joint mechanism with partially decoupled three-degree-of-freedom motion, a large angular range, a small number of passive pairs and a simple structure.

[0004] The technical solution of the present invention is: a three-degree-of-freedom parallel joint mechanism, including a fixing device, a cross hinge structure, an X-axis driver, a Y-axis driver, a Z-axis driver and a joint mechanism output shaft, the relative positions of the output shafts of the X-axis driver, the Y-axis driver and the Z-axis driver are fixed to each other by the fixing device, the output shaft of the X-axis driver drives the joint mechanism output shaft to rotate around a first axis through the cross hinge structure, the output shaft of the Y-axis driver drives the joint mechanism output shaft to rotate around a second axis, and the output shaft of the Z-axis driver drives the joint mechanism output shaft to rotate around a third axis.

[0005] Furthermore, the cross hinge structure includes two orthogonally arranged first U-shaped frames and second U-shaped frames, and a cross structure connected between the two U-shaped frames, and the first U-shaped frame and the second U-shaped frame are respectively connected to the output shaft of the X-axis drive and the output shaft of the joint mechanism.

[0006] Furthermore, the output shaft of the X-axis driver is connected to the X-axis rotation shaft, and the X-axis rotation shaft is connected to the first U-shaped frame. The rotation of the output shaft of the X-axis driver drives the first U-shaped frame, the second U-shaped frame, and the output shaft of the joint mechanism to rotate around the first axis, thereby realizing rotational movement of the first degree of freedom.

[0007] Furthermore, the output shaft of the Y-axis driver is connected to the Y-axis rotation axis, the Y-axis rotation axis is connected to the joint mechanism output shaft through the Y-axis connecting rod assembly, the Y-axis connecting rod assembly and the joint mechanism output shaft are connected through a rotating pair, and the rotation of the Y-axis driver output shaft drives the joint mechanism output shaft to rotate around the second axis, thereby realizing the rotational motion of the second degree of freedom.

[0008] Furthermore, the output shaft of the Z-axis driver is connected to the Z-axis rotation axis, the Z-axis rotation axis is connected to the joint mechanism output shaft through the Z-axis connecting rod assembly, the Z-axis connecting rod assembly and the joint mechanism output shaft are connected through a rotating pair, and the rotation of the Z-axis driver output shaft drives the joint mechanism output shaft to rotate around the third axis, thereby realizing the rotational motion of the third degree of freedom.

[0009] Further, the first axis coincides with the axis of the output shaft of the X-axis driver, and / or the second axis coincides with the axis of the output shaft of the Y-axis driver, and / or the third axis coincides with the axis of the output shaft of the Z-axis driver.

[0010] Furthermore, the output shaft of the joint mechanism can rotate continuously around the first axis in a single circle or multiple circles.

[0011] Furthermore, the output shaft of the X-axis driver is an integral structure with the X-axis rotation shaft, and / or the output shaft of the Y-axis driver is an integral structure with the Y-axis rotation shaft, and / or the output shaft of the Z-axis driver is an integral structure with the Z-axis rotation shaft.

[0012] Furthermore, the above-mentioned Y-axis connecting rod assembly and Z-axis connecting rod assembly respectively include a drive connecting member, a first connecting rod, a second connecting rod, and an output shaft connecting member; each component is connected in sequence through hinges; the drive connecting member is respectively connected to the Y-axis rotating shaft and the Z-axis rotating shaft, and the output shaft connecting member is respectively connected to the output shaft of the joint mechanism through bearings.

[0013] Furthermore, the intersection of the output shaft of the X-axis driver and the output shaft of the Y-axis driver coincides with the center of the cross structure; and / or the X-axis rotation axis is coaxially arranged with the output shaft of the joint mechanism, and its axis passes through the center of the cross structure.

[0014] The present invention has the following beneficial effects: the three-degree-of-freedom parallel joint mechanism of the present invention has a simple structure and can obtain a large angular range, especially the degree of freedom of rotation around the first axis (X axis) is infinite, while the angular range around the second axis (Y axis) and the third axis (Z axis) is ±90 degrees, and the angles of the two swinging movements around the second axis (Y axis) and the third axis (Z axis) are only determined by the Y-axis driver and the Z-axis driver, respectively, so that partial decoupling is achieved. The rotation in each direction can be performed separately, or two by two at the same time, or three directions at the same time. In addition to being used for the joint drive of the robot, the three-degree-of-freedom parallel joint mechanism of the present invention can be used for processing equipment because the output shaft can rotate continuously following the X-axis driver. The X-axis driver can also drive the wheel, and the entire mechanism can realize the control of the wheel posture. In addition, it can also be used for the drive of the three-degree-of-freedom moving platform, with strong versatility and good social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the parallel mechanism structure of Agile eye with three rotational degrees of freedom.

[0016] Figure 2 It is a schematic diagram of the structure of the present invention.

[0017] Figure 3 It is a schematic diagram of the present invention rotating around the X-axis.

[0018] Figure 4 It is a schematic diagram of the present invention rotating around the Y-axis.

[0019] Figure 5 It is a schematic diagram of the present invention rotating around the Z-axis.

[0020] Figure 6 It is a schematic diagram of the present invention rotating simultaneously around the three axes of X, Y and Z.

[0021] Figure 7 It is a schematic diagram of an application example of the present invention in a shoulder joint of a humanoid robot. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the 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 cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] like Figure 2 As shown, a three-degree-of-freedom parallel joint mechanism includes a fixing device 2, a cross hinge structure 14, an X-axis driver 15, a Y-axis driver 3 and a Z-axis driver 1. The axes of the output shafts of the X-axis driver 15, the Y-axis driver 3 and the Z-axis driver 1 may intersect in pairs or at a point, preferably orthogonal. The relative positions of the output shafts of the X-axis driver 15, the Y-axis driver 3 and the Z-axis driver 1 are relatively fixed by the fixing device 2. In this embodiment, the fixing device 2 includes two L-shaped fixing plates 2. The relative positions of the output shafts of the X-axis driver 15 and the Y-axis driver 3 are relatively fixed by one fixing plate 2, and the relative positions of the output shafts of the Y-axis driver 3 and the Z-axis driver 1 are relatively fixed by another fixing plate 2. As long as the relative fixation of the three can be achieved, other structural types of fixing devices can be used. The joint mechanism is fixed to other components through the fixing device 2, and the fixing device 2 can also be formed integrally with other components.

[0026] The cross hinge structure 14 includes two orthogonally arranged first U-shaped frames and second U-shaped frames, and a cross structure connected between the two U-shaped frames, the first U-shaped frame and the second U-shaped frame are respectively connected to the X-axis rotation shaft 17 and the joint mechanism output shaft 8, and the joint mechanism output shaft 8 can be connected to the moving platform. The X-axis rotation shaft 17 and the joint mechanism output shaft 8 are preferably coaxially arranged, and their axes preferably pass through the center of the cross structure.

[0027] The output shaft of the X-axis driver 15 is connected to the X-axis rotating shaft 17, and can drive the first U-shaped frame, the second U-shaped frame, and the joint mechanism output shaft 8 to rotate continuously around the first axis in a single circle or multiple circles to achieve rotational motion with a first degree of freedom.

[0028] The output shaft of the Y-axis driver 3 is connected to the Y-axis rotating shaft 18, and the Y-axis rotating shaft 18 is connected to the joint mechanism output shaft 8 through the Y-axis connecting rod assembly. The Y-axis connecting rod assembly and the joint mechanism output shaft 8 are connected through a rotating pair, preferably a first bearing 9. The rotation of the output shaft of the Y-axis driver 3 drives the joint mechanism output shaft 8 to rotate around the second axis, thereby realizing the rotational movement of the second degree of freedom. The rotation angle of the second degree of freedom can reach ±90 degrees.

[0029] The output shaft of the Z-axis driver 1 is connected to the Z-axis rotating shaft 19, and the Z-axis rotating shaft 19 is connected to the joint mechanism output shaft 8 through the Z-axis connecting rod assembly. The Z-axis connecting rod assembly and the joint mechanism output shaft 8 are connected through a rotating pair, preferably a second bearing 10. The rotation of the output shaft of the Z-axis driver 1 drives the joint mechanism output shaft 8 to rotate around the third axis, thereby realizing the rotational movement of the third degree of freedom. The rotation angle of the third degree of freedom can also reach ±90 degrees.

[0030] The first degree of freedom is preferably a roll degree of freedom, the second degree of freedom is preferably a pitch degree of freedom, and the third degree of freedom is preferably a yaw degree of freedom.

[0031] The first axis preferably coincides with the axis of the output shaft of the X-axis driver 15 , the second axis preferably coincides with the axis of the output shaft of the Y-axis driver 3 , and the third axis preferably coincides with the axis of the output shaft of the Z-axis driver 1 .

[0032] The above-mentioned Y-axis connecting rod assembly and Z-axis connecting rod assembly respectively include drive connecting parts 4, 16, first connecting rods 5, 13, second connecting rods 6, 12, and output shaft connecting parts 7, 11; each component is connected in sequence through hinges, the three hinges in the Y-axis connecting rod assembly can be parallel to the Z axis, and the three hinges in the Z-axis connecting rod assembly are parallel to the Y axis; the drive connecting parts 4, 16 are respectively connected to the Y-axis rotating shaft 18 and the Z-axis rotating shaft 19, and the output shaft connecting parts 7, 11 are respectively connected to the joint mechanism output shaft 8 through the first bearing 9 and the second bearing 10. The above-mentioned six hinges avoid the interference between the second degree of freedom movement around the second axis and the third degree of freedom movement around the third axis, and realize the decoupling of the pitch degree of freedom and the yaw degree of freedom. The Y-axis connecting rod assembly and the Z-axis connecting rod assembly are L-shaped as a whole, and other structural types of connecting components can be used.

[0033] When the joint mechanism output shaft 8 rotates continuously one circle or multiple circles around the first axis, it can also swing around the second axis and / or the third axis, and of course it does not need to swing around the Y axis and / or the Z axis.

[0034] The rotation and rotation angle of the second degree of freedom (pitch) and the third degree of freedom (yaw) depend only on the output of the respective drivers, i.e., the output of the Y-axis driver 3 and the X-axis driver 15. In order to maximize the rotation angle, the intersection of the output axis of the Z-axis driver 1, the output axis of the Y-axis driver 3, and the output axis of the X-axis driver 15 preferably coincides with the center of the cross structure.

[0035] The driver is a motor or a pneumatic swing cylinder or a hydraulic swing cylinder, and the driver may also include a reducer.

[0036] like Figure 3 As shown, the schematic diagram of the three-degree-of-freedom parallel joint mechanism of the present invention rotating around the X-axis does not interfere with the rotation of the Y-axis and the Z-axis, and the rotation angle depends on the motion output of the three drivers.

[0037] like Figure 4 As shown, the schematic diagram of the three-degree-of-freedom parallel joint mechanism of the present invention rotating around the Y axis does not interfere with the rotation of the X axis and the Z axis, and the rotation angle depends on the motion output of the Y axis driver 3.

[0038] like Figure 5 As shown, the schematic diagram of the three-degree-of-freedom parallel joint mechanism of the present invention rotating around the Z axis does not interfere with the rotation of the X axis and the Y axis, and the rotation angle depends on the motion output of the Z axis driver 1.

[0039] like Figure 6 As shown, the three-degree-of-freedom parallel joint mechanism of the present invention rotates around the three axes of X, Y, and Z at the same time, and the three axes rotate without interfering with each other. When the output shaft 8 of the joint mechanism rolls around the X axis and yaws around the Z axis, the Y-axis driver can still drive the output shaft 8 of the joint mechanism to pitch; when the output shaft 8 of the joint mechanism rolls around the X axis and pitches around the Y axis, the Z-axis driver can still drive the output shaft 8 of the joint mechanism to yaw.

[0040] like Figure 7 The figure shows an application example of the three-degree-of-freedom parallel joint mechanism of the present invention on a robot. The three-degree-of-freedom parallel joint mechanism can be used as a shoulder joint of a robot arm, and can realize rotation of the robot arm in three directions.

[0041] The three-degree-of-freedom parallel joint mechanism of the present invention can be used not only for driving the joints of a robot, but also for driving a three-degree-of-freedom platform, has strong versatility, and has good social and economic benefits.

[0042] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A three-degree-of-freedom parallel joint mechanism, comprising a fixing device (2), a cross hinge structure (14), an X-axis driver (15), a Y-axis driver (3), a Z-axis driver (1) and a joint mechanism output shaft (8), wherein the relative positions of the output shafts of the X-axis driver (15), the Y-axis driver (3) and the Z-axis driver (1) are fixed to each other by the fixing device (2), characterized in that: The output shaft of the X-axis driver (15) drives the joint mechanism output shaft (8) to rotate around the first axis through the cross hinge structure (14); the output shaft of the Y-axis driver (3) is connected to the Y-axis rotating shaft (18), and the Y-axis rotating shaft (18) is connected to the joint mechanism output shaft (8) through the Y-axis connecting rod assembly; the output shaft of the Z-axis driver (1) is connected to the Z-axis rotating shaft (19), and the Z-axis rotating shaft (19) is connected to the joint mechanism output shaft (8) through the Z-axis connecting rod assembly; the Y-axis connecting rod assembly and the Z-axis connecting rod assembly each include a driver connecting member (4, 16 ), a first connecting rod (5, 13), a second connecting rod (6, 12), and an output shaft connecting member (7, 11); each component is connected in sequence via hinges; the driver connecting members (4, 16) are respectively connected to the Y-axis rotating shaft (18) and the Z-axis rotating shaft (19); the output shaft connecting members (7, 11) are respectively connected to the joint mechanism output shaft (8) via a rotating pair; the output shaft of the Y-axis driver (3) drives the joint mechanism output shaft (8) to rotate around the second axis, and the output shaft of the Z-axis driver (1) drives the joint mechanism output shaft (8) to rotate around the third axis; The output shaft of the X-axis driver (15) and the X-axis rotation shaft (17) are an integrated structure, and / or the output shaft of the Y-axis driver (3) and the Y-axis rotation shaft (18) are an integrated structure, and / or the output shaft of the Z-axis driver (1) and the Z-axis rotation shaft (19) are an integrated structure.

2. A three-degree-of-freedom parallel joint mechanism according to claim 1, characterized in that: The cross hinge structure (14) comprises a first U-shaped frame and a second U-shaped frame which are arranged orthogonally, and a cross structure connected between the two U-shaped frames, wherein the first U-shaped frame and the second U-shaped frame are respectively connected to an output shaft of an X-axis driver (15) and an output shaft (8) of a joint mechanism.

3. A three-degree-of-freedom parallel joint mechanism according to claim 2, characterized in that: The X-axis rotating shaft (17) is connected to the first U-shaped frame, and the rotation of the output shaft of the X-axis driver (15) drives the first U-shaped frame, the second U-shaped frame, and the joint mechanism output shaft (8) to rotate around the first axis, thereby achieving a rotational movement with a first degree of freedom.

4. A three-degree-of-freedom parallel joint mechanism according to claim 1, 2 or 3, characterized in that: The first axis coincides with the axis of the output shaft of the X-axis driver (15), and / or the second axis coincides with the axis of the output shaft of the Y-axis driver (3), and / or the third axis coincides with the axis of the output shaft of the Z-axis driver (1).

5. A three-degree-of-freedom parallel joint mechanism according to claim 1, 2 or 3, characterized in that: The joint mechanism output shaft (8) can rotate continuously in a single circle or multiple circles around the first axis.

6. A three-degree-of-freedom parallel joint mechanism according to claim 3, characterized in that: The intersection of the output shaft of the X-axis driver (15) and the output shaft of the Y-axis driver (3) coincides with the center of the cross structure; and / or the X-axis rotation axis (17) is coaxially arranged with the output shaft (8) of the joint mechanism, and the axis thereof passes through the center of the cross structure.

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