CN212300247U - Detection system for dynamic error of grating ruler - Google Patents
Detection system for dynamic error of grating ruler Download PDFInfo
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- CN212300247U CN212300247U CN202021343321.9U CN202021343321U CN212300247U CN 212300247 U CN212300247 U CN 212300247U CN 202021343321 U CN202021343321 U CN 202021343321U CN 212300247 U CN212300247 U CN 212300247U
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Abstract
The utility model discloses a system for detecting the dynamic error of a grating ruler, which comprises a first device and a second device, wherein the first device is used for acquiring the real-time position of the grating ruler to be detected; the second device is used for determining the reference position of the grating ruler to be measured; the signal acquisition controller is used for sending the position signals acquired by the first device and the second device to the computer; and the computer compares the received position signals to determine the dynamic error of the grating ruler. The detection system adopts laser interference as a length reference, realizes the simulation of different operation working conditions of the grating ruler through a servo linear motor, designs a double-path signal acquisition and processing system based on the FPGA, realizes the synchronous acquisition of reference signals and real-time signals, and analyzes and displays the measurement result through data storage and subsequent transmission processing.
Description
Technical Field
The utility model relates to a grating chi performance detects technical field, more specifically relates to grating chi dynamic error's detecting system.
Background
The grating ruler is an important position feedback component and is widely applied to modern machining industries such as a numerical control machine tool and the like. High-performance grating scales, especially large-stroke high-precision absolute grating scales, are one of the technical bottlenecks of high-end full-closed-loop numerical control machines in China, and almost all rely on imports at present. In the development strategy of "2025 of chinese manufacture", it is proposed to accelerate the development of leading-edge technology and equipment of high-grade numerical control machines, etc., and to develop main functional components such as high-grade numerical control systems and gratings, etc., with the emphasis on improving reliability and accuracy retention, thereby accelerating the realization of industrialization.
At present, some researches are carried out in the aspects of static and dynamic characteristics research and dynamic detection of the grating ruler at home. The method mainly considers the influence of static geometric errors on the precision and does not carry out dynamic error analysis. The influence of factors such as deformation of a workbench and a guide rail on the precision of the grating ruler is analyzed by the university of the fertilizer industry, but the measurement error analysis is static analysis, and the influence of factors such as the running speed change and the vibration of the grating ruler on the dynamic precision is not considered. The grating ruler dynamic detection system built by Wuyubin and the like of Shenzhen university can realize the functions of automatic control, data acquisition and the like of grating ruler detection through a computer, the detection process is carried out under the condition of low speed and uniform speed, dynamic factors such as different running speeds, acceleration and vibration of the grating ruler in the test process and static factors such as temperature and the like are not considered, and the system realizes the automation of the static detection process rather than the dynamic performance detection.
The method is characterized in that the method comprises the steps of measuring the dynamic error of a grating ruler, and measuring the dynamic error of the grating ruler under a specific working condition.
The static error of the grating ruler is the error between the stable reading and the reference position after the reading head of the grating ruler stops at a certain position; the dynamic error of the grating ruler refers to the error between the real-time dynamic reading of the grating ruler and the real-time reference position of the grating ruler in the moving process of the reading head in the working state of the grating ruler.
SUMMERY OF THE UTILITY MODEL
In order to solve the problem, the utility model provides a grating chi dynamic error detecting system obtains grating chi dynamic error through the comparison of grating chi dynamic real-time position and reference position, can improve grating chi dynamic error measuring precision. The method specifically comprises the following steps:
the first device is used for acquiring the real-time position of the grating ruler to be measured;
the second device is used for determining the reference position of the grating ruler to be measured;
the signal acquisition controller is used for sending the position signals acquired by the first device and the second device to the computer;
and the computer compares the received position signals to determine the dynamic error of the grating ruler.
In some embodiments, the grating scale head is coupled to a moving slide. The real-time position of the grating ruler is a curve formed by a series of positions of the movable sliding block measured under working conditions of different speeds, accelerations and the like, and the reference position is a position curve of the movable sliding block measured by the grating ruler reference position determining device under the same working condition.
In some embodiments, the grating ruler is calibrated by using a high-precision position testing system. The second device comprises a laser interference system, wherein the laser interference system comprises a laser, an interference mirror and a reflecting mirror; laser after laser interference system's laser instrument jets out is divided into two bundles with certain small angle by the interference mirror, and in inciding to the speculum, in the speculum reflects, returns to the interference mirror along new light path, returns the light inlet of laser after the interference mirror closes to accomplish the straight line and measure, thereby confirm the reference position who obtains grating chi.
In some specific embodiments, the system for detecting the error of the grating ruler further comprises a guide rail and a movable slider which can slide along the direction of the guide rail; wherein the laser and the interference mirror are arranged on the guide rail in sequence; the reflecting mirror is positioned on the movable sliding block.
In some specific embodiments, the first device includes a grating scale reading head, and the grating scale reading head is used for acquiring a real-time position signal of the grating scale, where the mounting positions of the grating scale and the grating scale reading head are two cases:
(1) the grating ruler reading head is positioned on the movable sliding block, and the grating ruler is fixed on the guide rail, so that when the movable sliding block is displaced, the grating ruler reading head is also displaced, the relative distance between the grating ruler reading head and the grating ruler is changed, and the real-time position of the grating ruler is obtained.
(2) The grating ruler is located on the movable sliding block, and the grating ruler reading head is fixed on the guide rail, so that after the movable sliding block is displaced, the grating ruler is also displaced, and therefore the relative distance between the grating ruler reading head and the grating ruler is changed, and the real-time position of the grating ruler is obtained.
One of the difficulties in dynamic precision detection of a grating scale is high-speed synchronous acquisition of a real-time position signal of the grating scale to be detected and a reference position signal of the grating scale, and particularly, under the condition of high-speed operation, an error caused by a signal synchronous error is larger. The traditional data acquisition card based on a single chip microcomputer has the data reading speed of microsecond level, two paths of signals need to be read in turn in an alternate mode, the microsecond is needed when the two paths of signals are acquired once, the caused measurement error reaches several micrometers, and the detection requirement cannot be met for a high-precision grating ruler.
In order to avoid the synchronous error caused by signal acquisition, the utility model discloses a high-speed two-channel synchronous data acquisition system, in some specific implementation modes, the information acquisition controller includes first data acquisition module, second data acquisition module, first decay circuit, second decay circuit, FPGA control module, data cache module; the laser of the laser interference system is connected with the first attenuation circuit through the first data acquisition module; the grating ruler reading head is connected with the second attenuation circuit through the second data acquisition module; the first attenuation circuit and the second attenuation circuit are both connected with the FPGA control module, and the FPGA control module is connected with the computer through the data cache module.
In order to simulate the working condition of the grating ruler in actual use more accurately, in some specific embodiments, the grating ruler reading head movement driving system comprises a servo linear motor, the servo linear motor is controlled by a servo linear motor controller, and the servo linear motor controller is connected with a computer.
In some more specific embodiments, the servo linear motor comprises a rotor part and a stator part, wherein the rotor part is fixed with the movable sliding block, the stator part is fixed with the guide rail, when at least one set of detection data is generated through the computer, the computer sends a control signal to the servo linear motor controller so as to control and drive the servo linear motor to work, and the stator part moves to drive the movable sliding block to move together.
The utility model discloses above-mentioned laser instrument, interference mirror, guide rail, servo linear electric motor are arranged in on same work rack (shockproof platform).
In some specific embodiments, a temperature sensor and a vibration sensor are further arranged on the guide rail, and the temperature sensor and the vibration sensor are respectively used for monitoring the working temperature and the vibration condition of the guide rail.
In order to ensure the linearity and dynamic characteristics of the rail system, in some embodiments, the rail is an air bearing rail.
The utility model discloses a grating chi dynamic error detecting system adopts laser interference system as the length benchmark, realizes the simulation of the different operating condition of grating chi through servo linear electric motor, has designed FPGA-based double-circuit signal acquisition processing system, realizes that reference signal and real-time signal carry out synchronous acquisition, handles through data storage and follow-up transmission, carries out analysis display to measuring result.
In a second aspect, the present invention further provides a method for detecting dynamic errors of a grating ruler by using the system for detecting dynamic errors of a grating ruler, comprising the following steps:
(1) sending speed and acceleration instructions to a linear motor servo control system through a computer, enabling a rotor of a linear motor to drive a movable sliding block and a grating ruler reading head to move together, and processing signals acquired by the grating reading head through a signal processing system to obtain a dynamic real-time position curve P (T, v, a, T) of a grating ruler;
(2) in the movement process, a position curve L (T, v, a, T) obtained by processing a position signal of the moving slide block acquired by a reference position determining device (namely a laser, an interference mirror and a reflecting mirror) by a signal processing system is used as a reference position curve of the grating ruler;
(3) comparing the real-time position curve P (T, v, a, T) of the same set of grating ruler with the reference position curve L (T, v, a, T) to obtain the dynamic measurement error E (T, v, a, T) of the grating ruler, namely the formula (1)
E(t,v,a,T)＝P(t,v,a,T)-L(t,v,a,T) (1)
Wherein T is the measuring time, v is the moving speed of the moving slide block, a is the moving acceleration of the moving slide block, and T is the real-time environment temperature.
In some embodiments, the test data further includes a moving direction, and therefore, a return error is detected, wherein the return error is a difference between dynamic measurement errors measured in two opposite moving directions, that is, equation (2)
ΔE(x,v,a,T)＝Ef(x,v,a,T)-Eb(x,v,a,T) (2)
Where x is the return error measurement position, Ef(x, v, a, T) is measured by the formula (1)Obtaining dynamic measurement error of grating ruler in first moving direction, Eb(x, v, a, T) is a dynamic measurement error of the grating scale in a direction opposite to the first moving direction measured by the equation (1).
Drawings
Fig. 1 is a perspective view of the system for detecting dynamic errors of a grating ruler according to the present invention;
fig. 2 is a schematic diagram of the signal acquisition controller of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
As shown in fig. 1, the embodiment of the utility model provides a grating chi dynamic error detecting system, include: the grating scale reading head 4 is fixed on the moving slide block 3, the moving slide block 3 can slide on the guide rail 2, and the guide rail can be an air-float guide rail.
The grating ruler reference position signal determination device for acquiring the reference position signal can be a laser interference system, and the system comprises a laser 5 and an interference mirror 6 which are fixedly arranged on the guide rail 2, and a reflecting mirror 7 which is fixedly arranged on the movable sliding block 3, wherein the laser 5, the interference mirror 6 and the reflecting mirror 7 are aligned with each other along a light path in the direction of the guide rail 2. Therefore, the grating ruler dynamic error detection system can acquire the reference signal as the reference position signal through the laser interference system, and can realize higher-precision position reference.
The movable slide block 3 is driven by a grating scale reading head 4 moving and driving system to slide on the guide rail. The grating ruler reading head moving driving system comprises a servo linear motor 8, the servo linear motor 8 is controlled by a servo linear motor controller 9, and the servo linear motor controller 9 is connected with a computer 10.
The signal acquisition controller 11 is configured to collect a real-time position signal of the grating scale and a reference position signal of the grating scale and transmit the signals to a computer for processing. The signal acquisition controller 11 is provided with a first connecting terminal, a second connecting terminal and a third connecting terminal; the first connecting terminal is connected with the laser 5, the second connecting terminal is connected with the grating ruler reading head 4, and the third connecting terminal is connected with the computer 10.
The grating ruler dynamic error detection system of the embodiment adopts the laser interference system as the length reference, and corresponding instructions are input into the computer, so that the grating ruler reading head is driven to move, and different operation conditions of the grating ruler to be detected can be realized (for example, different speeds, acceleration and other conditions of the grating ruler can be realized). Easy to operate and control.
In this embodiment, the linear motor 8 is connected to the computer 10 through the linear motor servo controller 9, wherein: the linear motor 8 comprises a rotor part and a stator part, the rotor part is connected with the movable sliding block 3, and the stator part is fixed with the guide rail 2. The computer 10 controls the linear motor 8 through the linear motor servo controller 9, then controls the brake part to drive the movable slide block 3, and then moves the slide block 3 to drive the grating ruler reading head 4 to move, thereby realizing the working conditions of different speeds and accelerations of the grating ruler 15. And then can detect and feedback each item parameter of grating chi motion state.
In this embodiment, in the detection system, the data transmission line of the grating scale reading head 4, the air inlet pipe of the air-floating guide rail, and the like can move together with the movable slider 3.
In this embodiment, the system for detecting dynamic error of the grating ruler further includes a temperature sensor 12 and a vibration sensor 13 that can be installed on the air-float guide rail 2. The temperature sensor and the vibration sensor respectively monitor the temperature and the vibration condition of the test system, and provide temperature compensation and vibration compensation for reducing errors.
In this embodiment, the grating ruler 15 to be measured is fixed on the guide rail 2, and an air film is arranged between the movable slider 3 and the guide rail 2. Thus, the real-time position signal of the grating ruler is obtained by moving the grating ruler reading head 4 on the slide block 3.
In this embodiment, the system for detecting dynamic error of a grating ruler further includes a stage 1 for fixing the air-floating guide rail 2 and the linear electronic stator, and the stage 1 may be, for example, a vibration-isolated marble stage. Other parts in the grating ruler dynamic error detection system are fixed on the shock insulation marble rack, so that the error in the measurement process can be further reduced.
Fig. 2 is a block diagram showing an embodiment of the signal acquisition controller 11.
As shown in fig. 2, the information acquisition controller 11 includes a first data acquisition module (i.e., a high-speed AD chip 1), a second data acquisition module (i.e., a high-speed AD chip 2), a first attenuation circuit, a second attenuation circuit, an FPGA control module, and a data cache module; the first data acquisition module is respectively connected with a laser of the laser interference system and the first attenuation circuit, and the second data acquisition module is respectively connected with the grating ruler reading head and the second attenuation circuit; the first attenuation circuit and the second attenuation circuit are both connected with the FPGA control module, the FPGA control module is connected with the data cache module, and the FPGA control module is connected with the computer through the data cache module. By parallel high-speed double-channel synchronous acquisition, delay errors caused by transmission of data to a computer in the high-speed acquisition process are avoided.
The high-speed AD chip 1 and the high-speed AD chip 2 simultaneously carry out two-way data acquisition, respectively acquire real-time position signals of the laser interference system and the grating ruler, and carry out signal conversion and post-processing by the FPGA after the signal attenuation processing of the attenuation circuit. The arrangement of the attenuation circuit avoids delay errors caused by transmission to a computer in the high-speed data acquisition process, and the computer reads the cached measurement data and performs post-processing and display.
An embodiment of the utility model provides a grating chi dynamic error detection method, including following step:
(1) sending speed and acceleration instructions to a linear motor servo control system through a computer, enabling a rotor of a linear motor to drive a movable sliding block and a grating ruler reading head to move together, and processing signals acquired by the grating reading head through a signal processing system to obtain a dynamic real-time position curve P (T, v, a, T) of a grating ruler;
(2) in the movement process, a position curve L (T, v, a, T) obtained by processing a position signal of the moving slide block acquired by a reference position determining device (namely a laser, an interference mirror and a reflecting mirror) by a signal processing system is used as a reference position curve of the grating ruler;
(3) comparing the real-time position curve P (T, v, a, T) of the same set of grating ruler with the reference position curve L (T, v, a, T) to obtain the dynamic measurement error E (T, v, a, T) of the grating ruler, namely the formula (1)
E(t,v,a,T)＝P(t,v,a,T)-L(t,v,a,T) (1)
Wherein T is the measuring time, v is the moving speed of the moving slide block, a is the moving acceleration of the moving slide block, and T is the real-time environment temperature.
For step (1), the grating ruler dynamic error detection system generates at least one set of test data within the specification parameter range according to the specification parameters of the grating ruler to be detected, for example, the specification parameters generally include a speed range, an acceleration range, and the like (the general maximum working speed can reach 2m/s, and the maximum working acceleration is 100 m/s)2) The generated test data should be within the specification parameters of the grating ruler.
In the embodiment, the synchronous acquisition of the real-time position and the reference position is carried out through the test data, and the continuous output of the dynamic errors of the grating ruler under different motion working conditions is obtained. And determining the dynamic error of the grating ruler, and establishing a relation model of the dynamic error and factors such as speed, acceleration, temperature, vibration and the like, so that the dynamic precision of the grating ruler in actual use is predicted, and the dynamic precision of the grating ruler is improved.
When the test data also includes the moving direction, it is also necessary to detect the dynamic return error, which is the difference between the dynamic measurement errors measured in the two opposite moving directions, that is, equation (2)
ΔE(x,v,a,T)＝Ef(x,v,a,T)-Eb(x,v,a,T) (2)
Where x is the return error measurement position, Ef(x, v, a, T) is determined by the formula (1)Dynamic measurement error of grating scale in first moving direction, Eb(x, v, a, T) is a dynamic measurement error of the grating scale in a direction opposite to the first moving direction measured by the equation (1).
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.
Claims (7)
1. Detection system of grating chi dynamic error, its characterized in that includes:
the first device is used for acquiring the real-time position of the grating ruler to be measured;
the second device is used for determining the reference position of the grating ruler to be measured;
the signal acquisition controller is used for sending the position signals acquired by the first device and the second device to the computer;
and the computer compares the received position signals to determine the dynamic error of the grating ruler.
2. The system for detecting the dynamic error of the grating ruler as claimed in claim 1, further comprising a guide rail and a movable slider capable of sliding along the direction of the guide rail; the second device comprises a laser interference system, and the laser interference system comprises a laser, an interference mirror and a reflecting mirror; the laser and the interference mirror are sequentially arranged on the guide rail; the reflecting mirror is positioned on the movable sliding block.
3. The system for detecting the dynamic error of the grating ruler as claimed in claim 1, wherein the first device comprises a grating ruler reading head, and the grating ruler reading head is fixed on a movable sliding block or a guide rail.
4. The system for detecting the dynamic error of the grating ruler according to any one of the claims 1 to 3, wherein the information acquisition controller comprises a first data acquisition module, a second data acquisition module, a first attenuation circuit, a second attenuation circuit, an FPGA control module and a data cache module;
the laser of the laser interference system is connected with the first attenuation circuit through the first data acquisition module; the grating ruler reading head is connected with the second attenuation circuit through the second data acquisition module; the first attenuation circuit and the second attenuation circuit are both connected with the FPGA control module, and the FPGA control module is connected with the computer through the data cache module.
5. The system for detecting the dynamic error of the grating ruler as claimed in claim 3, wherein the grating ruler reading head is driven by a grating ruler reading head driving system, the grating ruler reading head driving system comprises a servo linear motor, and the computer controls the servo linear motor through a servo linear motor controller;
the stator of the servo linear motor is fixed with the guide rail, the movable sliding block is fixed with the rotor of the servo linear motor, and the rotor of the servo linear motor can drive the movable sliding block to move together.
6. The system for detecting the dynamic error of the grating ruler as claimed in any one of claims 2 to 3 or 5, wherein a temperature sensor and a vibration sensor are further disposed on the guide rail.
7. The system for detecting dynamic error of a grating ruler as claimed in claim 2, wherein the guide rail is an air-float guide rail.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113776439A (en) * | 2021-09-07 | 2021-12-10 | 中国科学院长春光学精密机械与物理研究所 | Method for reducing Abbe error of grating ruler |
| CN114526678A (en) * | 2022-02-24 | 2022-05-24 | 长光（沧州）光栅传感技术有限公司 | Quick detection device of grating ruler reading head signal |
| CN116045814A (en) * | 2023-04-03 | 2023-05-02 | 合肥安迅精密技术有限公司 | Method and device for evaluating signal quality of grating ruler and storage medium |
-
2020
- 2020-07-09 CN CN202021343321.9U patent/CN212300247U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113776439A (en) * | 2021-09-07 | 2021-12-10 | 中国科学院长春光学精密机械与物理研究所 | Method for reducing Abbe error of grating ruler |
| CN113776439B (en) * | 2021-09-07 | 2022-09-27 | 中国科学院长春光学精密机械与物理研究所 | A method of reducing Abbe error of grating ruler |
| CN114526678A (en) * | 2022-02-24 | 2022-05-24 | 长光（沧州）光栅传感技术有限公司 | Quick detection device of grating ruler reading head signal |
| CN114526678B (en) * | 2022-02-24 | 2023-09-22 | 长光（沧州）光栅传感技术有限公司 | Quick detection device for grating ruler reading head signals |
| CN116045814A (en) * | 2023-04-03 | 2023-05-02 | 合肥安迅精密技术有限公司 | Method and device for evaluating signal quality of grating ruler and storage medium |
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