Antenna spherical surface testing method based on mechanical arm

Abstract

The invention relates to an antenna spherical surface testing method based on a mechanical arm. A three-axis rotary table located in a darkroom and a tested antenna installed on the three-axis rotary table are included. A six-axis mechanical arm is arranged in the darkroom on one side of the three-axis rotary table, and a testing device is installed on a clamp at the tail end of the six-axis mechanical arm. According to the test method, the whole spherical surface formed by covering the antenna phase center point can be met, and all-directional, multi-angle and high-precision antenna radiation performance evaluation can be provided.

Description

Technical Field

[0001] The present invention relates to the field of communication-related technologies, and in particular to a spherical surface testing method of an antenna based on a robotic arm. Background Art

[0002] With the advancement of communication technology, especially the rapid development of 5G, satellite communications, millimeter wave communications and other fields, new antenna systems have shown diversified forms (such as large-scale array antennas, reconfigurable antennas, ultra-wideband antennas, etc.) and higher performance requirements. Traditional fixed test facilities are difficult to meet the comprehensive and high-precision testing needs of these complex antennas.

[0003] On the sphere formed by the phase center of the antenna, the probe moves point by point and measures the electromagnetic field of each spherical grid point, and then calculates the far-field pattern and related performance parameters of the antenna through the near-field to far-field transformation algorithm (such as Kirchhoff approximation, moment method, fast Fourier transform, etc.). To improve the test efficiency, an array composed of multiple probes can be used to measure the field strength of each point on the sphere simultaneously or sequentially, and the test efficiency can be improved by electronic switching or parallel processing. The measurement method using multiple probes is relatively expensive.

[0004] Whether it is a single probe or multiple probes, in order to obtain the electromagnetic field of the spherical grid points formed by the phase center of the antenna, the probe is usually installed on a curved guide rail, and the antenna is fixed on a precision turntable. The turntable can realize two-dimensional or three-dimensional rotation. The single probe moves along the curved guide rail (multiple probes are put into work on the curved guide rail in turn). Combined with the stepping or continuous rotation of the turntable, a complete antenna radiation pattern can be obtained.

[0005] The shortcomings of the prior art are:

[0006] 1. The probe is installed on the arc guide rail. The mechanical installation structure will occupy the moving space, resulting in a limited test range. It can only measure the radiation field of less than half of the spherical grid point. For the multiple probes measured in sequence, the amount of data obtained will be less, which cannot meet the full spherical coverage measurement of the antenna.

[0007] 2. The position and posture of the probe on the curved guide rail have errors caused by mechanical installation when calculated based on the radius and angle, and the position accuracy cannot be guaranteed. In addition, it is extremely inconvenient to lay the motor and RF cables on the curved guide rail, and interference will occur during movement, posing certain safety hazards.

[0008] 3. Different test mechanisms are required to complete different test functions. The arc guide rails and turntables are difficult to install and require regular calibration and maintenance. It is inconvenient to disassemble and assemble the devices when the site changes. In addition, mechanical equipment needs to be disassembled and assembled when the test functions are switched, which is inefficient.

[0009] 4. The cost of customized curved guide rails and three-dimensional rotating tables is high.

[0010] In view of the above-mentioned defects, the designers have actively carried out research and innovation in order to create a spherical antenna testing method based on a robotic arm to make it more valuable for industrial use. Summary of the invention

[0011] In order to solve any of the above technical problems, an object of the present invention is to provide an antenna spherical surface testing method based on a robotic arm.

[0012] To achieve the above object, the present invention adopts the following technical solution:

[0013] A robot-based antenna spherical surface testing method includes a three-axis turntable located in a darkroom and an antenna to be tested mounted on the three-axis turntable;

[0014] The following steps are involved:

[0015] Step S1, a six-axis robotic arm is arranged in a dark room on one side of a three-axis turntable, and a test device is installed on a fixture at the end of the six-axis robotic arm;

[0016] Step S2, the antenna under test is mounted on the polarization plane of the three-axis turntable, with the antenna port of the antenna under test facing upward and directly facing the wall of the darkroom to avoid being blocked by the robotic arm;

[0017] Step S3: At this time, the test device is an industrial camera, and the six-axis robotic arm carries the industrial camera to take pictures of the antenna under test from multiple angles to determine the coordinate system of the antenna under test;

[0018] Step S4, the test device at this time is a probe, and the six-axis robotic arm carries the probe to rotate along the horizontal plane around the phase center axis of the antenna under test, and makes a circular motion in the range of 0 to 90 degrees. After the six-axis robotic arm completes each semicircular arc trajectory movement, the polarization axis of the three-axis turntable rotates to set the step angle;

[0019] Step S5, repeating the above step S4, when the polarization axis of the three-axis turntable rotates one circle, the probe rotates 90° to switch to the cross-polarization mode, and the polarization axis of the three-axis turntable returns to the zero position;

[0020] Step S6, repeat the above step S4, when the polarization axis of the three-axis turntable rotates one circle, the rotation axis of the three-axis turntable rotates 90°;

[0021] Step S7, repeating the above step S4, when the polarization axis of the three-axis turntable rotates one circle, the probe rotates 90° to switch to the cross-polarization mode, and the polarization axis of the three-axis turntable returns to the zero position;

[0022] Step S8, repeat the above step S4, and the test ends when the polarization axis of the three-axis turntable rotates one circle.

[0023] As a further improvement of the present invention, the robotic arm control system is connected to the six-axis robotic arm control, the robotic arm control system is connected to the host computer through the TCP / IP communication protocol, the robotic arm control system is connected to the PLC through the EtherNet / IP communication protocol, and the PLC is connected to the three-axis turntable through the ProfiNet communication protocol.

[0024] As a further improvement of the present invention, the host computer is connected to the vector network analyzer via the TCP / IP communication protocol.

[0025] As a further improvement of the present invention, the vector network analyzer is a 3672D vector network analyzer.

[0026] As a further improvement of the present invention, the robot arm control system is connected to the industrial camera via the SocketMessage communication protocol.

[0027] As a further improvement of the present invention, the robot control system transmits the position and posture data of the six-axis robot to the host computer in real time, and the host computer synchronizes the posture coordinates of the six-axis robot with the data collected from the network analyzer.

[0028] As a further improvement of the present invention, the scanning period of the communication program of the robot control system is 8ms.

[0029] As a further improvement of the present invention, the six-axis robot arm is a FANUC industrial robot arm.

[0030] As a further improvement of the present invention, in step S3, the six-axis robotic arm carries an industrial camera to take pictures of the surface of the antenna under test, obtain the three-dimensional coordinate information of the surface of the antenna under test, and perform flatness analysis and calculation to evaluate the flatness of the surface of the antenna under test.

[0031] By means of the above scheme, the present invention has at least the following advantages:

[0032] The testing method of the present invention can satisfy the requirement of covering the entire sphere formed by the phase center point of the antenna, and can provide all-round, multi-angle, and high-precision antenna radiation performance evaluation.

[0033] The invention is based on the fact that the scanning mode can be quickly switched during the test process of the mechanical arm. The mechanical arm is easy to install and the scanning path can be flexibly planned according to the antenna characteristics and test requirements to meet the spherical scanning requirements of antennas of various shapes and sizes.

[0034] Compared with the single probe movement or multiple probe sequential scanning method on the arc guide rail, the scanning method based on the mechanical arm of the present invention saves the installation of other complex mechanical devices and significantly reduces the cost.

[0035] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 It is a structural schematic diagram of a method for testing the spherical surface of an antenna based on a mechanical arm of the present invention;

[0038] Figure 2 It is a system framework diagram related to the robot arm control system of the present invention;

[0039] Figure 3 It is a schematic diagram of the six-axis robot arm of the present invention driving the industrial camera to operate in the first plane in the three-coordinate system;

[0040] Figure 4 It is a schematic diagram of the six-axis robot arm of the present invention driving the industrial camera to operate in the second plane in the three-coordinate system;

[0041] Figure 5 It is a schematic diagram of the six-axis robot arm of the present invention driving the industrial camera to operate in the third plane of the three-coordinate system;

[0042] Figure 6 yes Figure 3 Schematic diagram of the central three-axis turntable after rotating 90°;

[0043] Figure 7 yes Figure 4 Schematic diagram of the central three-axis turntable after rotating 90°;

[0044] Figure 8 yes Figure 5 Schematic diagram of the three-axis turntable after rotating 90°.

[0045] The meanings of the various reference numerals in the figures are as follows.

[0046] Six-axis robotic arm 1, fixture 2, testing device 3, three-axis turntable 4, antenna under test 5. DETAILED DESCRIPTION

[0047] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0048] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, rather than all the embodiments. The components of the embodiment of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiment of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiment of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0049] Example

[0050] like Figures 1 to 8 As shown,

[0051] A robot-based antenna spherical surface testing method includes a three-axis turntable 4 located in a darkroom and a tested antenna 5 mounted on the three-axis turntable 4.

[0052] The following steps are involved:

[0053] Step S1, a six-axis robot arm 1 is arranged in a dark room on one side of a three-axis turntable 4, a test device 3 is installed on a fixture 2 at the end of the six-axis robot arm 1, and the six-axis robot arm 1 is a FANUC industrial robot arm;

[0054] Step S2, the antenna 5 to be tested is mounted on the polarization plane of the three-axis turntable 4, with the antenna port of the antenna 5 to be tested facing upward and directly facing the wall of the darkroom, avoiding the obstruction of the mechanical arm;

[0055] Step S3, at this time, the test device 3 is an industrial camera, and the six-axis robot arm 1 carries the industrial camera to take photos of the antenna 5 under test at multiple angles to determine the coordinate system of the antenna 5 under test;

[0056] Step S4, at this time, the test device 3 is a probe, and the six-axis robot arm 1 carries the probe and rotates around the phase center axis of the antenna 5 under test along the horizontal plane, and makes a circular motion in the range of 0 to 90 degrees. After the six-axis robot arm 1 completes each semicircular arc trajectory movement, the polarization axis of the three-axis turntable 4 rotates to set the step angle;

[0057] Step S5, repeating the above step S4, when the 4 polarization axes of the three-axis turntable rotate one circle, the probe rotates 90° to switch to the cross-polarization mode, and the 4 polarization axes of the three-axis turntable return to the zero position;

[0058] Step S6, repeat the above step S4, when the polarization axis of the three-axis turntable 4 rotates one circle, the rotation axis of the three-axis turntable 4 rotates 90°;

[0059] Step S7, repeating the above step S4, when the 4 polarization axes of the three-axis turntable rotate one circle, the probe rotates 90° to switch to the cross-polarization mode, and the 4 polarization axes of the three-axis turntable return to the zero position;

[0060] Step S8, repeat the above step S4, and the test ends when the polarization axis of the three-axis turntable 4 rotates one circle.

[0061] The robot control system connected to the six-axis robot 1 control is connected to the host computer through the TCP / IP communication protocol. The robot control system is connected to the PLC through the EtherNet / IP communication protocol. The PLC is connected to the three-axis turntable 4 through the ProfiNet communication protocol. The host computer is connected to the vector network analyzer through the TCP / IP communication protocol. The vector network analyzer is a 3672D vector network analyzer. The robot control system is connected to the industrial camera through the SocketMessage communication protocol.

[0062] The robot control system transmits the position and posture data of the six-axis robot 1 to the host computer in real time, and the host computer synchronizes the position and posture coordinates of the six-axis robot 1 with the data collected from the network analyzer. The scanning cycle of the robot control system communication program is 8ms.

[0063] In addition, in step S3, the six-axis robot arm 1 carries an industrial camera to take pictures of the surface of the antenna 5 under test, obtains the three-dimensional coordinate information of the surface of the antenna 5 under test, and performs flatness analysis and calculation to evaluate the flatness of the surface of the antenna 5 under test.

[0064] The first embodiment of the present invention:

[0065] The robot-based spherical antenna test method combines the high efficiency of automated equipment and the professionalism of test technology. It can provide all-round and multi-angle antenna radiation performance evaluation, which is of great value to antenna research and development, production and quality control. It is particularly suitable for large antennas, complex-shaped antennas or antenna testing in confined spaces.

[0066] The present invention uses a standardized industrial six-axis robot arm to replace the customized arc guide rail. In addition, the function of the three-axis turntable 4 is optimized, and the three-axis turntable 4 can realize the movement processes such as up and down lifting, horizontal rotation and polarization direction.

[0067] The present invention adopts FANUC industrial robot to replace the traditional scanning frame and rotating table to realize the relative position control of the test probe and the antenna 5 under test. By writing the KAREL program and importing it into the robot system, the robot control system realizes network communication with the host computer, PLC, industrial camera, etc. through TCP / IP, EtherNet / IP and SocketMessage, and the position and posture data of the robot are transmitted to the host computer in real time, and the host computer synchronizes the posture coordinates of the robot with the data collected from the network analyzer.

[0068] The main testing steps of the present invention are:

[0069] 1. According to the test requirements, the six-axis robot arm 1 and the three-axis turntable 4 are placed at appropriate positions in the darkroom.

[0070] 2. Install the antenna to be tested on the 4th polarization plane of the three-axis turntable, with the antenna opening facing upwards towards the wall of the darkroom, avoiding the obstruction of the six-axis robot arm 1.

[0071] 3. Install the camera on the end fixture of the six-axis robot arm 1. The six-axis robot arm 1 carries the camera to take pictures of the antenna to be tested from multiple angles to determine the coordinate system of the antenna to be tested.

[0072] 4. Replace the camera on the end fixture of the six-axis robot arm 1 with a probe.

[0073] 5. The six-axis robot arm 1 carries the probe and rotates around the antenna phase center axis in a circular motion within a range of 0 to 90 degrees along the horizontal plane. After each semicircular arc trajectory movement, the three-axis turntable 4 polarization axis rotates to set the step angle.

[0074] 6. Repeat step 5. After the 4th polarization axis of the three-axis turntable rotates one circle, the probe rotates 90° and switches to the cross-polarization mode. The 4th polarization axis of the three-axis turntable returns to the zero position.

[0075] 7. Repeat step 5. After the polarization axis of the three-axis turntable 4 rotates one circle, the rotation axis of the three-axis turntable 4 rotates 90°.

[0076] 8. Repeat step 5. After the 4th polarization axis of the three-axis turntable rotates one circle, the probe rotates 90° and switches to the cross-polarization mode. The 4th polarization axis of the three-axis turntable returns to the zero position.

[0077] 9. Repeat step 5. The test ends when the polarization axis 4 of the three-axis turntable rotates one circle.

[0078] The improvements of the present invention mainly lie in:

[0079] 1. It can achieve full coverage of the spherical surface

[0080] The present invention uses a standardized industrial six-axis robot to replace the customized arc guide rail, optimizes and improves the three-axis turntable structure, simplifies the test platform, and achieves full coverage of the spherical surface. The robot has multiple rotation joints and can achieve complex spatial trajectory movement. For antennas installed in complex structures or confined spaces, the robot can bypass obstacles and reach test locations that are difficult for conventional equipment to reach, which can meet full spherical coverage.

[0081] The robot arm uses precision servo motors and mature motion control algorithms. The servo motor encoder provides real-time position and attitude feedback, supports dynamic error compensation, and can achieve sub-millimeter or even higher positioning accuracy. In addition, the robot arm is equipped with collision detection sensors and safety protection mechanisms, which can automatically stop or adjust movement when obstacles or abnormal conditions are detected to protect the safety of equipment and personnel.

[0082] 2. Flexible switching of functional tests

[0083] The present invention utilizes the advantages of the mechanical arm and can quickly switch the test mode during the test process. For example, when changing to a different antenna test, only the software configuration parameters need to be changed, which greatly improves the test efficiency.

[0084] 3. The coordinate system calibration method of the antenna under test is simple and efficient, ensuring the test accuracy

[0085] In the present invention, during the calibration of the coordinate system of the antenna under test, the robot arm is equipped with a camera to take pictures of the surface of the object under test, obtain the three-dimensional coordinate information of the object surface, and perform flatness analysis and calculation to evaluate the flatness of the object surface, thereby avoiding the defects of manual measurement errors and high work intensity.

[0086] The main factors affecting the scanning flatness are the repetitive positioning accuracy of the mechanical arm and the offset error of the coordinate system. The repetitive positioning accuracy of the mechanical arm selected in the present invention is ±0.03mm, and the accuracy of the laser scanner can reach 0.02mm.

[0087] 4. Real-time data interaction between the robot and the host computer

[0088] The robotic arm control system and the host computer use TCP / IP communication. The communication program written in KAREL programming language is stable and efficient after compilation. After it is imported into the robot system, the robotic arm control system acts as a server to transmit the position and posture information to the host computer in real time. The communication program scanning cycle is about 8ms, so the posture data collection cycle is much smaller than the antenna index data collection cycle from the network, which fully meets the real-time requirements of antenna testing.

[0089] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implying the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0090] 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, it can be an electrical connection, it can be a direct connection, it can be indirectly connected through an intermediate medium, and 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.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A robot-based antenna spherical surface testing method, comprising a three-axis turntable (4) located in a darkroom and an antenna (5) to be tested mounted on the three-axis turntable (4); Features: The following steps are involved: Step S1, a six-axis robot arm (1) is arranged in a dark room on one side of a three-axis turntable (4), and a test device (3) is installed on a fixture (2) at the end of the six-axis robot arm (1); Step S2, the antenna (5) to be tested is mounted on the polarization plane of the three-axis turntable (4), with the antenna port of the antenna (5) to be tested facing upward and directly facing the wall of the darkroom, avoiding the obstruction of the mechanical arm; Step S3, at this time, the test device (3) is an industrial camera, and the six-axis robot arm (1) carries the industrial camera to take photos of the antenna (5) under test at multiple angles to determine the coordinate system of the antenna (5) under test; Step S4, at this time, the test device (3) is a probe, and the six-axis mechanical arm (1) carries the probe and rotates along the horizontal plane around the phase center axis of the antenna (5) under test, and performs a circular motion within the range of 0 to 90 degrees. After the six-axis mechanical arm (1) completes each semicircular arc trajectory movement, the polarization axis of the three-axis turntable (4) rotates to set a step angle; Step S5, repeating the above step S4, when the polarization axis of the three-axis turntable (4) rotates one circle, the probe rotates 90° to switch to the cross-polarization mode, and the polarization axis of the three-axis turntable (4) returns to the zero position; Step S6, repeating the above step S4, after the polarization axis of the three-axis turntable (4) rotates one circle, the rotation axis of the three-axis turntable (4) rotates 90°; Step S7, repeating the above step S4, when the polarization axis of the three-axis turntable (4) rotates one circle, the probe rotates 90° to switch to the cross-polarization mode, and the polarization axis of the three-axis turntable (4) returns to the zero position; Step S8, repeat the above step S4, and the test ends when the polarization axis of the three-axis turntable (4) rotates one circle.

2. The antenna spherical surface testing method based on a robotic arm as claimed in claim 1, characterized in that: A robotic arm control system connected to the control of the six-axis robotic arm (1), the robotic arm control system connected to a host computer via a TCP / IP communication protocol, the robotic arm control system connected to a PLC via an EtherNet / IP communication protocol, and the PLC connected to a three-axis turntable (4) via a ProfiNet communication protocol.

3. The antenna spherical surface testing method based on a robotic arm as claimed in claim 2, characterized in that: The host computer is connected with the vector network analyzer via TCP / IP communication protocol.

4. The antenna spherical surface testing method based on a robotic arm as claimed in claim 3, characterized in that: The vector network analyzer is a 3672D vector network analyzer.

5. The antenna spherical surface testing method based on a robotic arm as claimed in claim 2, characterized in that: The robotic arm control system is connected to the industrial camera via the SocketMessage communication protocol.

6. The antenna spherical surface testing method based on a robotic arm as claimed in claim 2, characterized in that: The robotic arm control system transmits the position and posture data of the six-axis robotic arm (1) to the host computer in real time, and the host computer synchronizes the position and posture coordinates of the six-axis robotic arm (1) with the data collected from the network analyzer.

7. The antenna spherical surface testing method based on a robotic arm as claimed in claim 6, characterized in that: The scanning period of the communication program of the robotic arm control system is 8ms.

8. The antenna spherical surface testing method based on a robotic arm as claimed in claim 1, characterized in that: The six-axis robot arm (1) is a FANUC industrial robot arm.

9. The antenna spherical surface testing method based on a robotic arm as claimed in claim 1, characterized in that: In step S3, the six-axis robot arm (1) carries an industrial camera to take pictures of the surface of the antenna (5) under test, obtains three-dimensional coordinate information of the surface of the antenna (5) under test, and performs flatness analysis and calculation to evaluate the flatness of the surface of the antenna (5) under test.

Images