Six-degree-of-freedom parallel device for large-range high-precision spatial pose measurement

Abstract

The invention discloses a six-degree-of-freedom parallel device for large-range high-precision spatial pose measurement, and the device comprises a lightweight movable platform which is used for connecting a measured device; the lightweight fixed platform is used for connecting a fixed coordinate system; the plurality of precise spherical hinges are connected to the bottom of the lightweight movable platform; the plurality of measuring support leg assemblies are respectively connected to the plurality of precise spherical hinges; and the plurality of offset universal hinges are fixed on the lightweight fixed platform, the bottom of the measuring support leg assembly is connected with the offset universal hinges, and the offset universal hinges can provide rotation of at least two degrees of freedom. According to the six-degree-of-freedom parallel device for large-range high-precision spatial pose measurement, the spatial pose measurement cost is reduced, the environmental adaptability of spatial pose measurement is improved, the spatial pose measurement range is expanded, and the spatial pose measurement precision is improved.

Description

Technical Field

[0001] The invention relates to the field of robot measurement technology, and in particular to a six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement. Background Art

[0002] In today's rapidly developing industrial automation field, multi-degree-of-freedom machines, especially industrial robots, have become an indispensable component of many production processes due to their excellent flexibility and high programmability. These robots are capable of performing complex tasks, from simple handling to precision assembly, and their application range covers almost all manufacturing fields. With the growing demand for industrial robots, scenarios of human-robot collaboration are becoming increasingly common. In this collaborative environment, it is crucial to ensure the quality and safety of the production process. To achieve this goal, regular and rigorous evaluation of the robot's accuracy and repeatability has become a key step in maintaining industrial production efficiency and reliability.

[0003] Accurately measuring the position and posture (i.e., posture) of the robot's end effector is an important part of evaluating its performance. At present, the method commonly used in the industry is to use multiple high-resolution cameras or self-calibrated optical vision systems to obtain accurate measurements of posture. Although this vision-based measurement technology can provide relatively accurate posture data, its accuracy is directly affected by the image resolution and the quality of camera calibration. Generally, the accuracy of this measurement technology ranges from tens of microns to several millimeters, but it also has some limitations, such as strong dependence on environmental conditions and lack of real-time performance. In addition to vision-based measurement methods, laser interferometer is also a high-end technology that can be used for precise spatial posture measurement. It can provide extremely high measurement accuracy, but due to its limited angular measurement range and high cost, laser interferometer is not suitable for all occasions, especially in application scenarios with harsh environments.

[0004] Based on the above technical problems, technical personnel in this field urgently need to develop a six-degree-of-freedom parallel device for large-range and high-precision spatial posture measurement to solve the problems of existing spatial posture measurement technologies such as high cost, small measurement range, strong environmental dependence, poor real-time performance and accuracy limitations. Summary of the invention

[0005] The purpose of the present invention is to provide a six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement, which can achieve a larger measurement range and obtain higher measurement accuracy.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement of the present invention comprises:

[0008] A lightweight moving platform for connecting to the device under test; and

[0009] Lightweight fixed platform, used to connect to the fixed coordinate system;

[0010] A plurality of precision ball hinges are connected to the bottom of the lightweight dynamic platform, and the precision ball hinges can provide rotation with multiple degrees of freedom;

[0011] A plurality of measuring leg assemblies, respectively connected to a plurality of the precision ball hinges;

[0012] The parallel device also includes:

[0013] A plurality of offset universal hinges are fixed on the lightweight fixed platform, the bottom of the measuring leg assembly is connected to the offset universal hinges, and the offset universal hinges can provide at least two degrees of freedom of rotation.

[0014] Furthermore, the measuring leg assembly comprises an upper leg lightweight anisotropic support plate and a lower leg lightweight anisotropic support plate which are arranged relatively up and down; and

[0015] Three linear guide rails are connected between the upper leg lightweight anisotropic support plate and the lower leg lightweight anisotropic support plate through screws;

[0016] An upper leg lightweight circular support plate and a lower leg lightweight circular support plate are arranged between the upper leg lightweight anisotropic support plate and the lower leg lightweight anisotropic support plate, and the three linear guide rails all pass through the upper leg lightweight circular support plate and the lower leg lightweight circular support plate;

[0017] A grating scale reading head fixed to the lightweight circular support plate of the lower leg through two reading head bases;

[0018] A grating scale support plate fixed between the upper leg lightweight anisotropic support plate and the upper leg lightweight circular support plate;

[0019] A grating ruler attached to the grating ruler support plate;

[0020] A reading head wiring board connected to the lower leg lightweight anisotropic support plate;

[0021] It also includes two limit pins arranged close to the grating scale support plate.

[0022] Furthermore, the measuring leg assembly also includes linear bearings fixed to the upper leg lightweight circular support plate and the lower leg lightweight circular support plate through retaining springs, the number of the upper and lower linear bearings and retaining springs are three, and the linear guide passes through the linear bearings.

[0023] Preferably, the precision ball hinge can provide three degrees of freedom of rotation, and the rotation directions are perpendicular to each other.

[0024] Preferably, the offset universal hinge can provide two degrees of freedom of rotation, and the rotation directions are perpendicular to each other.

[0025] In the above technical solution, the six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement provided by the present invention has the following beneficial effects:

[0026] The six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement of the present invention reduces the cost of spatial posture measurement, improves the environmental adaptability of spatial posture measurement, expands the range of spatial posture measurement, and improves the accuracy of spatial posture measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0028] Figure 1 A schematic diagram of the overall structure of a six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement provided by an embodiment of the present invention;

[0029] Figure 2 A schematic diagram of the structure of a precision ball joint of a six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement provided by an embodiment of the present invention;

[0030] Figure 3 A schematic diagram of the structure of a measurement leg assembly of a six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement provided by an embodiment of the present invention;

[0031] Figure 4 A schematic structural diagram of a six-degree-of-freedom parallel device offset universal joint for large-range high-precision spatial posture measurement provided by an embodiment of the present invention.

[0032] Description of reference numerals:

[0033] 1. Lightweight moving platform; 2. Precision ball hinge; 3. Measuring leg assembly; 4. Offset universal hinge; 5. Lightweight fixed platform;

[0034] 3-1. Lightweight anisotropic support plate for upper leg; 3-2. Screws; 3-3. Grating scale support plate; 3-4. Grating scale; 3-5. Linear guide; 3-6. Grating scale reading head; 3-7. Reading head base; 3-8. Lightweight circular support plate for lower leg; 3-9. Limit pin; 3-10. Retaining spring; 3-11. Lightweight circular support plate for upper leg; 3-12. Linear bearing; 3-13. Reading head wiring board; 3-14. Lightweight anisotropic support plate for lower leg. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0036] See also Figure 1 to Figure 4 As shown;

[0037] The six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement of the present invention comprises:

[0038] A lightweight moving platform 1, used for connecting to a device under test; and

[0039] A lightweight fixed platform 5, used for connecting to a fixed coordinate system;

[0040] A plurality of precision ball hinges 2 are connected to the bottom of the lightweight dynamic platform 1, and the precision ball hinges 2 can provide rotation with multiple degrees of freedom;

[0041] A plurality of measuring leg assemblies 3, respectively connected to the plurality of precision ball hinges 2;

[0042] The parallel device also includes:

[0043] A plurality of offset universal hinges 4 are fixed on the lightweight fixed platform 5, and the bottom of the measuring leg assembly 3 is connected to the offset universal hinge 4, and the offset universal hinge 4 can provide at least two degrees of freedom of rotation. Specifically, in this mechanism, the lightweight fixed platform 5 is connected in a fixed coordinate system, and the lightweight moving platform 1 is connected to the device under test. At the same time, during measurement, the measuring leg assembly 3 is ensured to be in the middle position of the measurement, so as to maximize the measurement range, thereby meeting the application of the parallel mechanism under the condition of a large measurement range.

[0044] As a further introduction to this embodiment, the measuring leg assembly 3 includes an upper leg lightweight anisotropic support plate 3-1 and a lower leg lightweight anisotropic support plate 3-14 which are arranged relatively up and down; and

[0045] Three linear guide rails 3-5 are connected between the upper leg lightweight anisotropic support plate 3-1 and the lower leg lightweight anisotropic support plate 3-14 through screws 3-2;

[0046] The upper leg lightweight circular support plate 3-11 and the lower leg lightweight circular support plate 3-8 are arranged between the upper leg lightweight anisotropic support plate 3-1 and the lower leg lightweight anisotropic support plate 3-14, and the three linear guide rails 3-5 all pass through the upper leg lightweight circular support plate 3-11 and the lower leg lightweight circular support plate 3-8;

[0047] A grating scale reading head 3-6 fixed on the lower leg lightweight circular support plate 3-8 through two reading head bases 3-7;

[0048] A grating scale support plate 3-3 fixed between the upper leg lightweight anisotropic support plate 3-1 and the upper leg lightweight circular support plate 3-11;

[0049] A grating ruler 3-4 adhered to the grating ruler support plate 3-3;

[0050] A reading head wiring board 3-13 connected to the lower leg lightweight anisotropic support plate 3-14;

[0051] It also includes two limit pins 3-9 arranged close to the grating scale support plate 3-3, and the measuring leg assembly 3 realizes the mechanical limit function through the two limit pins 3-9.

[0052] As a further introduction to this embodiment, the measuring leg assembly 3 also includes a linear bearing 3-12 fixed to the upper leg lightweight circular support plate 3-11 and the lower leg lightweight circular support plate 3-8 by a retaining spring 3-10, and the number of the upper and lower linear bearings 3-12 and retaining springs 3-10 are three, and the linear guide rail 3-5 passes through the linear bearing 3-12.

[0053] It should be noted that the measuring principle of the measuring leg assembly 3 is to connect the measured device with the lightweight moving platform 1, drive the lightweight moving platform 1 to produce posture changes, so that the lightweight moving platform 1 causes the measuring leg assembly 3 to expand and contract, and the precision ball joint 2 and the offset universal joint 4 to rotate to perform spatial posture measurement. The system can obtain nanometer-level measurement accuracy in a working space of tens of centimeters. By integrating a high-precision grating ruler on the upper leg of the measuring leg assembly 3, integrating the grating ruler reading head 3-6 on the lower leg of the measuring leg assembly 3, measuring the relative motion between the upper leg and the lower leg of the leg assembly 3, and solving the posture of the lightweight moving platform 1 through forward kinematics.

[0054] As a preferred technical solution of this embodiment, in order to meet the application of joint hinges in three degrees of freedom, the precision ball hinges 2 are provided with a total of six, which are evenly distributed at 120° in pairs and installed on the lightweight dynamic platform 1. The precision ball hinges 2 can provide three degrees of freedom rotation, and the rotation directions are perpendicular to each other.

[0055] As a preferred technical solution of this embodiment, in order to meet the application of the joint hinge in two degrees of freedom, the offset universal hinges 4 are provided with a total of six, which are evenly distributed at 120° in pairs and installed on the lightweight fixed platform 5. The offset universal hinges 4 can provide two degrees of freedom of rotation, and the rotation directions are perpendicular to each other.

[0056] In the above technical solution, the six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement provided by the present invention has the following beneficial effects:

[0057] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement, characterized in that: The parallel device comprises: A lightweight moving platform (1) for connecting to a device under test; and A lightweight fixed platform (5) for connecting to a fixed coordinate system; A plurality of precision ball hinges (2), all connected to the bottom of the lightweight dynamic platform (1), the precision ball hinges (2) being capable of providing rotation with multiple degrees of freedom; A plurality of measuring leg assemblies (3) are respectively connected to the plurality of precision ball hinges (2); The parallel device also includes: A plurality of offset universal hinges (4) are fixed on the lightweight fixed platform (5); the bottom of the measuring leg assembly (3) is connected to the offset universal hinges (4); and the offset universal hinges (4) can provide at least two degrees of freedom of rotation.

2. The six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement according to claim 1, characterized in that: The measuring leg assembly (3) comprises an upper leg lightweight anisotropic support plate (3-1) and a lower leg lightweight anisotropic support plate (3-14) which are arranged relatively up and down; and Three linear guide rails (3-5) are connected between the upper leg lightweight anisotropic support plate (3-1) and the lower leg lightweight anisotropic support plate (3-14) through screws (3-2); An upper leg lightweight circular support plate (3-11) and a lower leg lightweight circular support plate (3-8) are arranged between the upper leg lightweight anisotropic support plate (3-1) and the lower leg lightweight anisotropic support plate (3-14), and the three linear guide rails (3-5) all pass through the upper leg lightweight circular support plate (3-11) and the lower leg lightweight circular support plate (3-8); A grating scale reading head (3-6) fixed on the lower leg lightweight circular support plate (3-8) via two reading head bases (3-7); A grating scale support plate (3-3) fixed between the upper leg lightweight anisotropic support plate (3-1) and the upper leg lightweight circular support plate (3-11); A grating ruler (3-4) adhered to the grating ruler support plate (3-3); A reading head wiring board (3-13) connected to the lower leg lightweight anisotropic support plate (3-14); It also includes two limit pins (3-9) arranged close to the grating scale support plate (3-3).

3. The six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement according to claim 2, characterized in that: The measuring leg assembly (3) further comprises a linear bearing (3-12) fixed to the upper leg lightweight circular support plate (3-11) and the lower leg lightweight circular support plate (3-8) via a retaining spring (3-10), the number of the upper and lower linear bearings (3-12) and retaining springs (3-10) being three each, and the linear guide rail (3-5) passing through the linear bearing (3-12).

4. The six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement according to any one of claims 1 to 3, characterized in that: A total of six precision ball hinges (2) are provided, which are evenly distributed at 120° in pairs and installed on the lightweight dynamic platform (1). The precision ball hinges (2) can provide three-degree-of-freedom rotation, and the rotation directions are perpendicular to each other.

5. The six-degree-of-freedom parallel device for large-scale high-precision spatial posture measurement according to any one of claims 1 to 3, characterized in that: A total of six offset universal hinges (4) are provided, which are evenly distributed at 120° in pairs and installed on the lightweight fixed platform (5). The offset universal hinges (4) can provide two degrees of freedom of rotation, and the rotation directions are perpendicular to each other.

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