A rigid five-axis serial-parallel hybrid robot positioning platform

Abstract

The present invention discloses a rigid five-axis serial-parallel hybrid robot positioning platform, including a support frame, the support frame is fixedly connected to a hollow rotating platform assembly, the hollow rotating platform assembly is fixed to a rigid parallel 3-RRR mechanism, the rigid parallel 3-RRR mechanism includes a static platform and a dynamic platform assembly, the back of the static platform is fixed to a mechanism drive assembly, the mechanism drive assembly provides power for the rigid parallel 3-RRR mechanism, and the dynamic platform assembly includes three branch chains, each branch chain is composed of an input rod, a driven rod and two connecting shafts in series. The present invention is driven by five axes in total, and can achieve multi-point positioning within a certain space. Since the core positioning function is realized by a rigid parallel 3-RRR mechanism and combined with two motion axes, precise positioning within a large range of motion can be achieved.

Description

Technical Field

[0001] The invention relates to the field of precision positioning processing, and in particular to a rigid five-axis serial-parallel hybrid robot positioning platform. Background Art

[0002] In the fields of semiconductor lithography, micro-machinery, precision measurement, ultra-precision machining, micro-assembly, biological cell manipulation and nanotechnology, very precise positioning and very fine movement are required, so high-performance precision positioning workbenches have become the technical support for these fields. In addition to micro-nano positioning accuracy, excellent stability, rigidity and rapid response, the precision positioning platform is also required to have a large motion stroke. In order to better obtain these outstanding performances, parallel mechanisms are often used in the design of precision positioning platforms. Parallel mechanisms can overcome the shortcomings of traditional series mechanisms such as low rigidity, poor load-bearing and large motion vibration during the movement of the end moving platform.

[0003] At present, although parallel robots have better accuracy and load capacity than serial robots, they have not been widely adopted like serial robots due to a series of difficulties such as complex structure, small motion range, high processing cost and high assembly precision requirements. Although they can achieve micron or even higher positioning accuracy with high-performance drivers and excellent driving methods, their working range is still small. A few commercial precision positioning platforms have a range of motion of millimeters, but their accuracy is not high enough. In response to these problems, domestic and foreign scholars have done a lot of research and proposed many design solutions with large stroke and high precision, but these platforms are often large in overall size, high in processing cost, and very complex in control model. Therefore, it is very necessary to design a positioning platform that can balance the motion space, positioning accuracy and design domain size, and a solvable and accurate control model, so that it can achieve high-speed and high-precision positioning in a larger three-dimensional motion space. Summary of the invention

[0004] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, an object of the present invention is to provide a rigid five-axis serial-parallel hybrid robot positioning platform.

[0005] The present invention can complete spatial positioning, obtain a large stroke and high-precision positioning performance, and realize accurate position control and posture control.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A rigid five-axis serial-parallel hybrid robot positioning platform comprises a support frame, wherein the support frame is fixedly connected to a hollow rotating platform assembly, the hollow rotating platform assembly is fixed to a rigid parallel 3-RRR mechanism, the rigid parallel 3-RRR mechanism comprises a static platform and a dynamic platform assembly, the back of the static platform is fixed to a mechanism drive assembly, the mechanism drive assembly provides power for the rigid parallel 3-RRR mechanism, the dynamic platform assembly comprises three branch chains, each branch chain is composed of an input rod, a driven rod and two connecting shafts connected in series, the three branch chains are connected in parallel to a dynamic platform located at the center of the mechanism, the input rod is connected to a drive output shaft of the mechanism drive assembly, and performs planar rotational motion around the drive output shaft.

[0008] Furthermore, the rotation centers of the outer sides of the input rods of the three branches of the moving platform assembly constitute the three vertices of a first equilateral triangle, and the rotation centers of the three connecting shafts on the inner sides of the three branches constitute the three vertices of a second equilateral triangle. The vertices of the first equilateral triangle and the second equilateral triangle are respectively connected through the input rods and driven rods of the three branches.

[0009] Furthermore, the circumscribed circle radius of the first equilateral triangle corresponds to the design parameter C of the rigid parallel 3-RRR mechanism; for any branch chain, in order from the outside to the inside, the center distance from the rotation center of the outside of the input rod to the first connecting shaft is the design parameter A; the center distance from the first connecting shaft to the second connecting shaft is the design parameter B; the circumscribed circle radius of the second equilateral triangle corresponds to the design parameter E of the rigid parallel 3-RRR mechanism; when the moving platform is in the initial state, the centers of the two equilateral triangles coincide, and the second equilateral triangle formed by the rotation centers of the three inner connecting shafts has an initial deflection angle compared to the first equilateral triangle formed by the rotation center of the outside of the input rod, corresponding to the initial posture angle of the moving platform, expressed as t0, where the ratio A:B:E:C=1:1:0.33:1.

[0010] Furthermore, when the rigid parallel 3-RRR mechanism is in the initial state, the centers of the first and second equilateral triangles coincide, and the two equilateral triangles have an initial deflection angle t0 of -140°.

[0011] Furthermore, the static platform is provided with three calibration holes, which are arranged 120° in a tri-symmetrical manner around the circumferential center of the static platform, and are used for initial position calibration of the three input rods.

[0012] further,

[0013] A through hole is provided at the center of the connecting end cover of the drive output shaft and the input rod, and a thread passes through the through hole to cooperate with the central internal thread of the drive output shaft, so that the connecting end cover of the drive output shaft cooperates with the end face of the drive output shaft to determine the axial position of the input rod and the moving platform, and a set screw is used to radially lock the input rod and the drive output shaft to achieve synchronous and co-rotation of the drive output shaft and the input rod.

[0014] Furthermore, the hollow rotating platform assembly includes:

[0015] Rotation drive: used to provide a power source for the rotation of the rigid parallel 3-RRR mechanism, including a servo motor;

[0016] Hollow rotating platform: used to transmit the rotational motion of the servo motor to the output end of the rotating platform;

[0017] Rotating cylinder: installed at the output end of the rotating platform, used to install the rigid parallel 3-RRR mechanism.

[0018] Furthermore, it also includes a linear translation module installed at the center of the moving platform.

[0019] Furthermore, the support frame includes two side right-angled triangle frames and a front main board, and the two side right-angled triangle frames are arranged on both sides of the front main board.

[0020] Furthermore, the input rod and the drive output shaft transmit torque via a keyway.

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0022] (1) In a rigid five-axis serial-parallel hybrid robot positioning platform, the rigid parallel 3-RRR mechanism is the core positioning mechanism of the invention, which determines the upper limit of the positioning accuracy of the overall positioning platform. The rigid parallel 3-RRR mechanism consists of a static platform, an input rod, a driven rod and a dynamic platform. The parts of the entire component are divided into multiple layers in the axial direction, which can achieve the maximum axial space utilization without interference;

[0023] (2) In the present invention, the rigid parallel 3-RRR mechanism can be flexibly designed to obtain a rigid parallel 3-RRR mechanism with different performances through kinematic design parameters A, B, E, C, and t0; in the design of such a rigid five-axis serial-parallel hybrid robot positioning platform, the rigid parallel 3-RRR mechanism can be replaced by various types of planar rigid parallel positioning mechanisms, not limited to the 3-RRR mechanism exemplified in the present invention, and all can achieve large stroke and high precision positioning characteristics.

[0024] (3) In the present invention, the cylindrical connector at the end of the hollow rotating platform assembly is used to connect the rotating table of the hollow rotating platform and the static platform of the rigid parallel 3-RRR mechanism. The cylindrical integrated structure is designed to improve the positioning accuracy of the operating surface of the rigid parallel 3-RRR mechanism and reduce the angular deviation and processing cumulative error between the rotating table and the operating plane of the rigid parallel 3-RRR mechanism.

[0025] (4) In the present invention, three positioning holes are opened on the static platform of the rigid parallel 3-RRR mechanism for calibrating the initial position of the input end of the rigid parallel 3-RRR mechanism; the input rod of the rigid parallel 3-RRR mechanism is directly fixed to the output shaft of the 3-RRR rotary drive device, thereby reducing other unnecessary transmission parts and ensuring the accuracy and transmission efficiency of the overall positioning platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The utility model is an axonometric schematic diagram of a rigid five-axis serial-parallel hybrid robot positioning platform of the present invention.

[0027] Figure 2 It is a left view schematic diagram of a rigid five-axis serial-parallel hybrid robot positioning platform of the present invention.

[0028] Figure 3 The present invention Figure 1 Schematic diagram of the structure of the middle support frame.

[0029] Figure 4 The present invention Figure 1 Schematic diagram of the structure of the hollow rotating platform assembly.

[0030] Figure 5 The present invention Figure 1 Schematic diagram of the structure of the medium static platform.

[0031] Figure 6 It is a structural schematic diagram of a rigid parallel 3-RRR dynamic platform assembly according to an embodiment of the present invention.

[0032] Figure 7 Schematic diagram of the structure of the linear translation module according to an embodiment of the present invention.

[0033] The figure shows:

[0034] Figure 1 Middle: 1-support frame; 2-hollow rotating platform assembly; 3-static platform; 4-dynamic platform assembly; 5-linear translation module.

[0035] Figure 3 Middle: 11- supporting side panel; 12- front main board.

[0036] Figure 4Middle: 21 - rotating driving member; 22 - hollow rotating platform; 23 - rotating cylindrical member.

[0037] Figure 5 Middle: 31-mechanism driving assembly; 32-calibration hole.

[0038] Figure 6 In the middle: 41-input rod; 42-connecting end cover; 43-fastening threaded hole; 44-connecting shaft; 45-driven rod; 46-connecting shaft; 47-moving platform. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below in conjunction with the examples, but the embodiments of the present invention are not limited thereto.

[0040] Example

[0041] like Figure 1 and Figure 2 As shown, a rigid five-axis serial-parallel hybrid robot positioning platform includes a support frame 1 for supporting the entire mechanism, a hollow rotating platform assembly 2 fixedly connected to the support frame, and the rigid parallel 3-RRR mechanism includes a static platform 3 and a dynamic platform assembly 4. The back of the static platform is fixed to the mechanism drive assembly 31, and the mechanism drive assembly 31 provides power for the rigid parallel 3-RRR mechanism. The dynamic platform assembly includes three branches, each of which is composed of an input rod 41, a driven rod 45 and two connecting shafts in series. The three branches are connected in parallel to the dynamic platform located at the center of the mechanism. The input rod is connected to the drive output shaft of the mechanism drive assembly and performs planar rotation around the drive output shaft. The linear translation module 5 is installed on the dynamic platform 47 located at the center of the rigid parallel 3-RRR mechanism.

[0042] like Figure 3 As shown, the support frame 1 as the support of the whole mechanism has two side right-angled triangle frames 11, which are arranged on both sides of the front main board 12. The front main board 12 is used to install all other components of the positioning platform; the side right-angled triangle frame 11 is a standard part, and its lower end can be fixed to the bottom platform with a matching hole position by bolts, and is used to connect and fix the front main board 12.

[0043] like Figure 4As shown, the hollow rotating platform assembly 2 is used to provide the entire mechanism with a rotational freedom without rotation angle restrictions. The rotating drive member 21 is the power source of the rotational freedom, and a servo motor is selected here to achieve high-precision angle control; the hollow rotating platform 22 is a standard part, which is used to transmit the rotational motion of the motor to the output end of the rotating platform on the other side, and at the same time plays a role in deceleration and torque increase; the rotating cylindrical member 23 is installed at the output end of the rotating platform of the hollow rotating platform 22, and rotates with the output end of the rotating platform, and is used to install the positioning mechanism of the remaining four axes. The static platform is installed on the rotating cylindrical member.

[0044] like Figure 5 As shown, the static platform is fixed to the end of the rotating cylinder 23 by bolts, and the mechanical drive assembly 31 is in contact with the back end surface of the static platform 3 and is installed on the static platform by bolts to provide power for the rigid parallel 3-RRR mechanism. The calibration holes 32 of the input rods of the rigid parallel 3-RRR mechanism are arranged on the static platform of the rigid parallel 3-RRR mechanism and are arranged 120° three-symmetrically around the center of the circle, which are used for the initial position calibration of the three input rods 41 of the rigid parallel 3-RRR mechanism connecting rod and the moving platform 47.

[0045] like Figure 6 As shown, the moving platform assembly is composed of three branches with the same structure arranged in a trisymmetrical manner. Each branch chain includes an input rod 41, a driven rod 45 and two connecting shafts connected in series, a connecting shaft 44 specifically realizes the connection between the input rod and the driven rod, and a connecting shaft 46 realizes the connection between the driven rod and the moving platform. The three branches are connected in parallel to the moving platform located at the center of the mechanism, and the input rod is connected to the drive output shaft of the mechanism drive assembly, and performs a planar rotation motion around the drive output shaft.

[0046] like Figure 7 The figure shows the specific structure of the linear translation module.

[0047] The specific connections are as follows:

[0048] The input rod 41 has one end directly fixedly connected to the rotary motor drive output shaft of the mechanism drive assembly, and performs planar rotational motion around the drive output shaft. The connecting end cover 42 of the drive output shaft and the input rod is in contact with the input rod 41 through four bolts spaced 90 degrees apart. There is a through hole at the center of the connecting end cover 42 of the drive output shaft and the input rod, which can pass through the bolts to cooperate with the central internal thread of the drive output shaft of the mechanism drive assembly 31, so that the back of the connecting end cover 42 of the drive shaft and the input rod is tightly matched with the end face of the drive output shaft of the rigid parallel 3-RRR mechanism drive assembly 31, so that the axial position of the rigid parallel 3-RRR mechanism connecting rod and the moving platform assembly 4 can be determined.

[0049] A fixing threaded hole 43 for the input rod is drilled on the input rod 41 of the rigid parallel 3-RRR mechanism, and a fixing screw can be used to radially lock the output shaft of the mechanism drive assembly 31 and the input rod 41 to ensure that the output shaft of the mechanism drive assembly 31 and the input rod 41 rotate synchronously and in the same position without slipping.

[0050] The connecting shaft 44 between the input rod and the driven rod is used to connect the input rod 41 and the driven rod 45 of the rigid parallel 3-RRR mechanism, and acts as a bearing; the connecting shaft 46 between the driven rod and the moving platform is used to connect the driven rod 45 and the moving platform 47, and acts as a bearing.

[0051] Furthermore, the rotation centers of the outer sides of the input rods of the three branches of the moving platform assembly constitute the three vertices of the first equilateral triangle.

[0052] The rotation centers of the three connecting shafts 46 inside the three branch chains constitute the three vertices of a second equilateral triangle.

[0053] The vertices of the first equilateral triangle and the second equilateral triangle are connected respectively through the input rod and the driven rod of the three branches.

[0054] The circumscribed circle radius of the first equilateral triangle corresponds to the design parameter C of the rigid parallel 3-RRR mechanism; for any branch chain, in order from the outside to the inside, the center distance from the rotation center of the outside of the input rod to the first connecting shaft, that is, the connecting shaft 44, is the design parameter A; the center distance from the first connecting shaft to the second connecting shaft, that is, the connecting shaft 46, is the design parameter B; the circumscribed circle radius of the second equilateral triangle corresponds to the design parameter E of the rigid parallel 3-RRR mechanism; when the moving platform is in the initial state, the center of the two equilateral triangles is The centers of the two connecting shafts coincide with each other, and the second equilateral triangle formed by the rotation centers of the three inner connecting shafts has an initial deflection angle compared to the first equilateral triangle formed by the rotation center of the outer side of the input rod, corresponding to the initial posture angle of the moving platform, expressed as t0, where the ratio A:B:E:C=1:1:0.33:1, when the parameters are designed according to the above A:B:E:C=1:1:0.33:1 and t0=-140°, the plane reachable motion range of the center point of the moving platform is a circle with a radius of R, and at this time A:R=1:0.85. And at any position within the plane reachable motion range, the moving platform can rotate around the center point of the moving platform at any point by -5°~5°, which can meet the adjustment requirements of a certain posture during work.

[0055] When the rigid parallel 3-RRR mechanism is in the initial state, the centers of the first and second equilateral triangles coincide, and the two equilateral triangles have an initial deflection angle t0 of -140°. The above initial deflection angle maximizes the motion range of the moving platform.

[0056] The connecting rod of the rigid parallel 3-RRR mechanism and the input rod of the moving platform are connected to the output shaft of the driving device of the rigid parallel 3-RRR mechanism static platform and its driving assembly. The two transmit torque through a key and are fixed at the same time by end bolts and side set screws; the static platform of the rigid parallel 3-RRR mechanism rotates with the movement of the hollow rotating platform assembly, thereby enabling the entire rigid parallel 3-RRR mechanism to obtain a rotation capability without rotation angle restriction.

[0057] The invention discloses a rigid five-axis serial-parallel hybrid robot positioning platform, wherein a support frame is used to install and fix the entire positioning platform and its driving devices, and its supporting side plates can be fixed on a standard experimental shock-absorbing platform with threaded holes by bolts; a hollow rotating platform assembly is installed on the support frame, which is used to install and connect a rigid parallel 3-RRR mechanism on the one hand, and to provide a rotational freedom without rotation angle restriction on the other hand; a rigid parallel 3-RRR mechanism static platform and a driving assembly thereof are installed on a rotating cylindrical member of the hollow rotating platform assembly, which are used to install and fix a driving motor of the rigid parallel 3-RRR mechanism and to perform initial positioning and provide power for an input rod of the rigid parallel 3-RRR mechanism; a rigid parallel 3-RRR mechanism connecting rod and a moving platform are the core parts of the invention for realizing the positioning function, and can realize precise positioning within a plane, wherein a total of three branch chains are arranged in a trisymmetrical form, and the input rod of each branch chain is independently driven and fixedly connected to the driving motor by connecting an end cover and a fixing threaded hole on a side surface, and the three chains move in coordination to control the moving platform in the center to perform precise positioning of the three degrees of freedom in the plane. The linear translation module is installed on the moving platform of the rigid parallel 3-RRR mechanism, and can perform planar motion as the moving platform is positioned. Its output shaft can be installed with different actuators to achieve different functions. The present invention is driven by five axes and can achieve multi-point positioning within a certain space. Since the core positioning function is realized by the rigid parallel 3-RRR mechanism and combined with two motion axes, precise positioning within a larger range of motion can be achieved.

[0058] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the 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 rigid five-axis serial-parallel hybrid robot positioning platform, characterized in that: It includes a support frame, the support frame is fixedly connected to a hollow rotating platform assembly, the hollow rotating platform assembly is fixed to a rigid parallel 3-RRR mechanism, the rigid parallel 3-RRR mechanism includes a static platform and a dynamic platform assembly, the back of the static platform is fixed to a mechanism drive assembly, the mechanism drive assembly provides power for the rigid parallel 3-RRR mechanism, the dynamic platform assembly includes three branch chains, each branch chain is composed of an input rod, a driven rod and two connecting shafts connected in series, the three branch chains are connected in parallel to the dynamic platform located at the center of the mechanism, the input rod is connected to a drive output shaft of the mechanism drive assembly, and performs a planar rotation motion around the drive output shaft; The rotation centers of the outer sides of the input rods of the three branch chains of the moving platform assembly constitute the three vertices of a first equilateral triangle, the rotation centers of the three connecting shafts on the inner sides of the three branch chains constitute the three vertices of a second equilateral triangle, and the vertices of the first equilateral triangle and the second equilateral triangle are connected respectively through the input rods and driven rods of the three branch chains; The circumscribed circle radius of the first equilateral triangle corresponds to the design parameter C of the rigid parallel 3-RRR mechanism; for any branch chain, in order from the outside to the inside, the center distance from the rotation center of the outside of the input rod to the first connecting shaft is the design parameter A; the center distance from the first connecting shaft to the second connecting shaft is the design parameter B; the circumscribed circle radius of the second equilateral triangle corresponds to the design parameter E of the rigid parallel 3-RRR mechanism; when the moving platform is in the initial state, the centers of the two equilateral triangles coincide, and the second equilateral triangle formed by the rotation centers of the three inner connecting shafts has an initial deflection angle compared to the first equilateral triangle formed by the rotation center of the outside of the input rod, corresponding to the initial posture angle of the moving platform, expressed as t0, where the ratio A:B:E:C = 1:1:0.33:

1.

2. The rigid five-axis serial-parallel hybrid robot positioning platform according to claim 1, characterized in that: When the rigid parallel 3-RRR mechanism is in the initial state, the centers of the first and second equilateral triangles coincide, and the two equilateral triangles have an initial deflection angle t0 of -140°.

3. The rigid five-axis serial-parallel hybrid robot positioning platform according to claim 1, characterized in that: The static platform is provided with three calibration holes, which are arranged 120° in a trisymmetrical manner around the circumferential center of the static platform and are used for initial position calibration of the three input rods.

4. The rigid five-axis serial-parallel hybrid robot positioning platform according to claim 1, characterized in that: A through hole is provided at the center of the connecting end cover of the drive output shaft and the input rod, and a thread passes through the through hole to cooperate with the central internal thread of the drive output shaft, so that the connecting end cover of the drive output shaft cooperates with the end face of the drive output shaft to determine the axial position of the input rod and the moving platform, and a set screw is used to radially lock the input rod and the drive output shaft to achieve synchronous and co-rotation of the drive output shaft and the input rod.

5. The rigid five-axis serial-parallel hybrid robot positioning platform according to claim 1, characterized in that: The hollow rotating platform assembly comprises: Rotation drive: used to provide a power source for the rotation of the rigid parallel 3-RRR mechanism, including a servo motor; Hollow rotating platform: used to transmit the rotational motion of the servo motor to the output end of the rotating platform; Rotating cylinder: installed at the output end of the rotating platform, used to install the rigid parallel 3-RRR mechanism.

6. The rigid five-axis serial-parallel hybrid robot positioning platform according to any one of claims 1 to 5, characterized in that: It also includes a linear translation module installed at the center of the moving platform.

7. The rigid five-axis serial-parallel hybrid robot positioning platform according to claim 1, characterized in that: The support frame includes two side right-angled triangle frames and a front main board, and the two side right-angled triangle frames are arranged on both sides of the front main board.

8. The rigid five-axis serial-parallel hybrid robot positioning platform according to claim 2, characterized in that: The input rod and the drive output shaft transmit torque through a keyway.

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