Dynamic calibration device based on laser interference and synchronous triggering

Abstract

The utility model discloses a dynamic calibration device based on laser interference and synchronous triggering, and the device comprises a linear motion guide rail which comprises a fixed workbench and a movable workbench; a measurement target of a calibrated instrument and a reflecting mirror of the laser interferometer are carried on the movable workbench; an interference mirror of the laser interferometer is fixed on the fixed workbench; the synchronous trigger is provided with a plurality of output ports for outputting synchronous pulse signals and is respectively connected with the laser interferometer and the calibrated instrument; the laser interferometer responds to the synchronous pulse signal to measure the displacement amount of the movable workbench; the calibrated instrument measures the position information of the measurement target in response to the synchronization pulse signal; the upper computer is used for receiving the displacement amount of the movable workbench and the position information of the measurement target. A laser interferometer is used as a length standard device, a synchronous trigger is used as a time standard device, and a traceability chain of dynamic calibration on length and time is perfected by synchronously triggering measurement of the standard device and a calibrated instrument.

Description

Technical Field

[0001] The utility model relates to the field of measurement and testing, in particular to a dynamic calibration device based on laser interference and synchronous triggering. Background Art

[0002] In recent years, large-scale coordinate measuring instruments represented by laser trackers are often used in dynamic measurement scenarios such as component adjustment and docking. Therefore, the dynamic measurement performance of large-scale coordinate measuring instruments, especially the instantaneous error, must be calibrated. At present, only the "JJF 1242-2021 Laser Tracking Three-Dimensional Coordinate Measurement System Calibration Specification" involves dynamic parameter calibration. It is recommended to use a standard circular trajectory generator as the standard equipment. The laser tracker tracks and measures the spherical reflection target that moves with the standard circular trajectory generator. A set of measurement points in one circle is taken to fit the circumference and calculate the diameter to test the dynamic indication error and dynamic indication change.

[0003] However, the "JJF 1242-2021 Laser Tracking Three-Dimensional Coordinate Measurement System Calibration Specification" does not specify the metrological requirements for the time parameters of the standard circular trajectory generator, and the circular fitting ignores the time information in the calculation of the dynamic indication error and the dynamic indication change, and the traceability chain of the dynamic calibration at the time level is missing. Therefore, the dynamic calibration device based on the standard circular trajectory generator is not suitable for the traceability of time-varying parameters such as the instantaneous error of large-scale coordinate measuring instruments such as laser trackers. Utility Model Content

[0004] In order to make up for the problem that the dynamic calibration device based on the standard circle trajectory generator is not suitable for tracing time-varying parameters such as instantaneous errors of large-size coordinate measuring instruments such as laser trackers, the utility model provides a dynamic calibration device based on laser interference and synchronous triggering, which adopts a laser interferometer as a length standard and a synchronous trigger as a time standard. The laser interferometer and the calibrated instrument are triggered at the same time to track and measure the reflector and the measurement target moving along a straight line, which is used to calculate the instantaneous length indication error of the calibrated instrument and improve the traceability chain of dynamic calibration in length and time.

[0005] To achieve the above-mentioned purpose, the utility model provides a dynamic calibration device based on laser interference and synchronous triggering, which comprises: a linear motion guide rail, a laser interferometer, a synchronous trigger and a host computer;

[0006] The linear motion guide rail includes a fixed workbench and a movable workbench that slides along a straight line under the drive of a driving mechanism; the movable workbench carries a measuring target of the calibrated instrument and a reflector of a laser interferometer; the fixed workbench is fixed with an interferometer of the laser interferometer;

[0007] A synchronous trigger, which has a plurality of output ports for outputting synchronous pulse signals and is respectively connected to the laser interferometer and the instrument to be calibrated;

[0008] The reflector, the interferometer and the laser interferometer form an interference measurement optical path. The laser interferometer measures the displacement of the moving workbench in response to the synchronization pulse signal of the synchronization trigger; the calibrated instrument measures the position information of the measurement target in response to the synchronization pulse signal.

[0009] The host computer is configured to receive the displacement of the moving table measured by the laser interferometer and the position information of the measuring target measured by the calibrated instrument.

[0010] The further improvement of the utility model lies in that: the linear motion guide rail includes a marble base, and the movable workbench is slidably arranged on the marble base through a metal linear guide rail; the driving mechanism is a linear motor, which is connected to the host computer; a grating ruler is arranged between the marble base and the movable workbench; the linear electric mechanism and the grating ruler form a closed-loop control to drive the movable workbench to move along the guide rail at a set speed and acceleration.

[0011] The further improvement of the utility model is that the linear motion guide rail comprises a marble guide rail, the movable workbench is an air-floating workbench slidably arranged on the marble guide rail, and the driving mechanism is a friction wheel driven by a servo motor.

[0012] A further improvement of the utility model is that the reflector, the interferometer and the laser interferometer are collinear, and a straight line passing through the centers of the three is parallel to the moving direction of the movable workbench.

[0013] The further improvement of the utility model is that: the synchronization trigger includes a GNSS antenna, a GNSS taming clock, a microprocessor, and a signal distributor;

[0014] The GNSS antenna receives the standard time signal from the GNSS onboard atomic clock;

[0015] The GNSS disciplined clock is used as the clock source of the synchronization trigger. It uses the standard time signal to discipline its internal constant temperature crystal oscillator and provide the clock signal for the synchronization trigger.

[0016] The microprocessor divides the clock signal to generate a pulse signal of a predetermined frequency;

[0017] The signal distributor copies the pulse signal into multiple synchronous pulse signals and sends them to the laser interferometer and the instrument to be calibrated through each output port.

[0018] The further improvement of the utility model is that: the microprocessor is connected to the host computer through a serial communication module; the synchronous trigger also includes a power module to supply power to each active device in the synchronous trigger.

[0019] The further improvement of the utility model is that the instrument to be calibrated includes a laser tracker; and the measurement target includes a spherical reflection target.

[0020] The solution provided by the utility model has the following technical effects: a dynamic calibration device based on laser interference and synchronous triggering adopts a laser interferometer as a length standard and a synchronous trigger as a time standard, and through synchronous triggering of the standard and measurement with the calibrated instrument, the traceability chain of dynamic calibration in length and time is improved.

[0021] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a dynamic calibration device based on laser interferometry and synchronous triggering;

[0023] Figure 2 It is the structure diagram of synchronous trigger.

[0024] The accompanying drawings are denoted as follows:

[0025] 1——Linear motion guide

[0026] 101 - Mobile workbench

[0027] 102——Fixed workbench

[0028] 2——Laser interferometer

[0029] 201——Reflector

[0030] 202——Interferometer

[0031] 3 - Synchronous trigger

[0032] 4——Dynamic calibration software

[0033] 5——Laser Tracker

[0034] 501——Spherical reflective target DETAILED DESCRIPTION

[0035] The following describes the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0036] It should be noted that the illustrations provided in the following embodiments are only used to schematically illustrate the basic concept of the present invention, and thus the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0037] like Figure 1 As shown, an embodiment of the utility model provides a dynamic calibration device based on laser interference and synchronous triggering, which includes: a linear motion guide rail 1, a laser interferometer 2, a synchronous trigger 3 and a host computer 4. In this embodiment, the dynamic calibration device based on laser interference and synchronous triggering is applicable to a large-size coordinate measuring instrument with a pulse signal external trigger measurement function. In a specific embodiment, the calibrated instrument includes a laser tracker 5; the measurement target includes a spherical reflection target 501.

[0038] The linear motion guide rail 1 is a motion generating mechanism of the dynamic calibration device, which includes a fixed workbench 102 and a movable workbench 101 that slides in a straight line under the drive of a driving mechanism. The movable workbench carries the measurement target of the instrument to be calibrated and the reflector 201 of the laser interferometer 2; the fixed workbench 102 is fixed to one end of the linear motion guide rail 1, and the interferometer 202 of the laser interferometer 2 is fixed to the fixed workbench.

[0039] In some embodiments, the linear motion guide 1 includes a marble base, and the mobile workbench 101 is slidably arranged on the marble base through a metal linear guide; the driving mechanism is a linear motor connected to the host computer; a grating ruler is arranged between the marble base and the mobile workbench 101; the linear electric mechanism and the grating ruler form a closed-loop control to drive the mobile workbench 101 to move along the guide rail at a set speed and acceleration. This linear motion guide has a simple structure, and can use commercially available linear motors and grating rulers for high-performance motion control. The dynamic calibration device of the linear motion guide 1 provides stable test conditions.

[0040] In other embodiments, the linear motion guide rail 1 includes a marble guide rail, the movable workbench 101 is an air-floating workbench slidably disposed on the marble guide rail, and the driving mechanism is a friction wheel driven by a servo motor.

[0041] The laser interferometer 2, as a length standard of the dynamic calibration device, has a pulse signal external trigger measurement function and can be triggered by the synchronization trigger 3. The laser interferometer 2 is fixed beside the fixed workbench 102 of the linear motion guide 1, and forms an interference measurement optical path with the interferometer 202 on the fixed workbench 102 and the reflector 201 on the mobile workbench 101, and measures the displacement of the mobile workbench 101 when triggered by the synchronization pulse signal output by the synchronization trigger 3.

[0042] like Figure 2 As shown, the synchronization trigger 3 is a time standard of the dynamic calibration device, which has multiple output ports for outputting synchronization pulse signals, respectively connected to the laser interferometer 2 and the calibrated instrument. The synchronization trigger 3 includes a GNSS antenna, a GNSS disciplined clock, a microprocessor, and a signal distributor.

[0043] The GNSS antenna is placed in an open space outdoors. The GNSS antenna receives the standard time signal from the GNSS satellite-borne atomic clock. The GNSS disciplined clock is used as the clock source of the synchronization trigger 3. It uses the standard time signal to discipline its internal constant temperature crystal oscillator and provide a clock signal for the synchronization trigger. The microprocessor divides the clock signal to generate a pulse signal of a predetermined frequency. Frequency division is a standard function of modern embedded processors. Mainstream MCU chips have a wealth of on-chip timer peripherals, and the required frequency division requirements can be achieved by configuring the corresponding registers.

[0044] In this embodiment, the microprocessor is connected to the host computer through a serial communication module. The frequency of the clock signal provided by the GNSS disciplined clock to the synchronization trigger 3 is 10MHz. The microprocessor divides the 10MHz clock signal to produce a pulse signal of a specified frequency. The signal distributor copies the pulse signal into multiple synchronous pulse signals, and each synchronous pulse signal is sent to the laser interferometer 2 and the calibrated instrument through each output port. In this embodiment, the signal distributor has four output ports to achieve synchronous output of 4 pulse signals, wherein output port 1 is connected to the trigger signal input port of the laser interferometer 2, output port 2 is reserved for the laser tracker 5 as the calibrated instrument, and output ports 3 and 4 are left floating. The power supply module provides 5V power supply for the synchronization trigger 3. In this embodiment, the relative frequency accuracy of the synchronization pulse signals output by each output port of the synchronization trigger 3 is better than 10 -11 , the delay between signals in different paths is better than 5ns.

[0045] The host computer 4 is configured to receive the displacement of the movable worktable 101 measured by the laser interferometer 2 and the position information of the measurement target measured by the calibrated instrument.

[0046] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A dynamic calibration device based on laser interference and synchronous triggering, characterized in that include: Linear motion guide rail (1), laser interferometer (2), synchronous trigger (3) and host computer (4); The linear motion guide rail (1) comprises a fixed workbench (102) and a movable workbench (101) which slides in a straight line direction under the drive of a driving mechanism; the movable workbench (101) carries a measurement target of a calibrated instrument and a reflector (201) of a laser interferometer (2); the fixed workbench (102) is fixed with an interferometer (2) of the laser interferometer (2); A synchronous trigger (3), which has a plurality of output ports for outputting synchronous pulse signals and is respectively connected to the laser interferometer (2) and the instrument to be calibrated; A reflector (201), an interferometer (202) and a laser interferometer (2) form an interference measurement optical path; the laser interferometer (2) measures the displacement of the movable workbench (101) in response to a synchronization pulse signal of the synchronization trigger (3); and the calibrated instrument measures the position information of the measurement target in response to the synchronization pulse signal. The host computer (4) is configured to receive the displacement of the movable workbench (101) measured by the laser interferometer (2) and the position information of the measurement target measured by the calibrated instrument.

2. A dynamic calibration device based on laser interference and synchronous triggering according to claim 1, characterized in that: The linear motion guide rail (1) comprises a marble base, and the movable workbench (101) is slidably arranged on the marble base via a metal linear guide rail; the driving mechanism is a linear motor connected to the host computer; a grating ruler is arranged between the marble base and the movable workbench (101); the linear motor mechanism and the grating ruler form a closed-loop control to drive the movable workbench (101) to move along the guide rail at a set speed and acceleration.

3. A dynamic calibration device based on laser interference and synchronous triggering according to claim 1, characterized in that: The linear motion guide rail (1) comprises a marble guide rail, the movable workbench (101) is an air-floating workbench slidably arranged on the marble guide rail, and the driving mechanism is a friction wheel driven by a servo motor.

4. A dynamic calibration device based on laser interference and synchronous triggering according to claim 1, characterized in that: The reflector (201), the interferometer and the laser interferometer (2) are collinear, and a straight line passing through the centers of the three is parallel to the movement direction of the movable workbench (101).

5. The dynamic calibration device based on laser interference and synchronous triggering according to claim 1, characterized in that: The synchronization trigger (3) includes a GNSS antenna, a GNSS discipline clock, a microprocessor, and a signal distributor; The GNSS antenna receives a standard time signal from a GNSS onboard atomic clock; The GNSS disciplined clock is used as the clock source of the synchronization trigger. It uses the standard time signal to discipline its internal constant temperature crystal oscillator and provide the clock signal for the synchronization trigger. The microprocessor divides the clock signal to generate a pulse signal of a predetermined frequency; The signal distributor copies the pulse signal into multiple synchronous pulse signals, and sends them to the laser interferometer (2) and the instrument to be calibrated through the output ports respectively.

6. A dynamic calibration device based on laser interference and synchronous triggering according to claim 5, characterized in that: The microprocessor is connected to the host computer through a serial communication module; the synchronous trigger also includes a power module to supply power to each active device in the synchronous trigger.

7. The dynamic calibration device based on laser interference and synchronous triggering according to claim 1, characterized in that: The calibrated instrument includes a laser tracker (5); and the measurement target includes a spherical reflection target (501).

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