Device and method for measuring and correcting temperature drift of motion angle of galvanometer

Abstract

The invention discloses a device and a method for measuring and correcting temperature drift of a galvanometer motion angle, relates to the technical field of photoelectric device measurement, and solves the problems that the implementation process of an existing measurement method through a prediction model is complicated, the relation between the temperature change and the angle of a galvanometer cannot be directly measured and the like. The power supply supplies power to the galvanometer control box and the galvanometer body, the galvanometer body and the galvanometer control box are located in the high-low temperature box, the theodolite is located outside the high-low temperature box, the theodolite and the high-low temperature box are both located on the table top of the air flotation vibration isolation table, the computer is connected with the galvanometer control box through an RS422-USB connecting line, and upper computer software is installed in the computer. And the control module is used for controlling the motion angle of the galvanometer body and transmitting the real-time position to upper computer software to confirm whether the position is in place or not. According to the method, the correlation between the actual angle and the measured angle is a nonlinear relation, and the closest quadratic or cubic mathematical relation is obtained by adopting a nonlinear fitting method, so that subsequent angle compensation is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of photoelectric device measurement, and in particular to a novel device and method for measuring the angle temperature drift of a galvanometer. Background Art

[0002] Galvanometers have the advantages of high precision, large scanning angle, and fast response speed, and have been applied in precision laser processing, laser radar, and optical imaging. Galvanometers are one of the core components of optical scanning systems, and their scanning speed and accuracy are crucial. Temperature drift will cause deviations in the scanning angle of the galvanometer, reduce position control accuracy, and affect imaging quality. Therefore, the measurement of temperature drift of the galvanometer motion angle is a key indicator to measure its performance.

[0003] In recent years, with the rapid development of the high-precision optical industry, higher requirements have been placed on the position accuracy of the galvanometer. In order to achieve better processing technology and reduce the impact of temperature changes on the galvanometer angle accuracy, in temperature drift measurement, it is necessary to measure the galvanometer movement angle at different temperatures in real time to obtain temperature drift data for further analysis and processing.

[0004] In the prior art, the patent with application number CN201910739730.6 discloses a thermal drift measurement method for a scanning galvanometer laser processing system. The invention predicts the thermal drift of a scanning galvanometer laser processing system by establishing a prediction model of temperature difference and light spot coordinate difference. However, the patent measures the temperature and light spot coordinate values ​​through sensors and calculates the prediction model. The implementation process is relatively complicated, and the relationship between the galvanometer temperature change and the angle is not directly measured.

[0005] In view of the problem that the prior art is relatively complex and the relationship between temperature and angle change cannot be directly obtained, no effective solution has been proposed. Therefore, the present invention provides a device for measuring the temperature drift of the galvanometer motion angle. Summary of the invention

[0006] The present invention provides a device for measuring the temperature drift of the galvanometer motion angle in order to solve the problems that the existing measurement method has a complex process of implementing the prediction model and cannot directly measure the relationship between the galvanometer temperature change and the angle.

[0007] A device for measuring the temperature drift of the motion angle of a galvanometer, the device comprising an external power supply, a computer, a high and low temperature box, an air-floating vibration isolation table, a galvanometer body, a galvanometer control box and a theodolite;

[0008] The power supply is used to power the galvanometer control box and the galvanometer body. The galvanometer body and the galvanometer control box are located in a high and low temperature box, the theodolite is located outside the high and low temperature box, and both the theodolite and the high and low temperature box are located on the table of the air floating vibration isolation table. The computer is connected to the galvanometer control box via an RS422 to USB cable. The host computer software is installed inside the computer to control the movement angle of the galvanometer body and transmit the real-time position to the host computer software.

[0009] The present invention also provides a method for measuring the temperature drift of the galvanometer motion angle, which is implemented by the device for measuring the temperature drift of the galvanometer motion angle, and the method is implemented by the following steps:

[0010] Step 1: Place the galvanometer body and the galvanometer control box in a high and low temperature box, send a control command to the galvanometer control box through the host computer, control the galvanometer body to move to the specified position, and set the initial angle of the galvanometer body to 0°;

[0011] Step 2: Set the high and low temperature box to enter the temperature cycle mode, use the theodolite to aim at the galvanometer body, and record the current actual angle position, the given expected angle position energy and the current temperature;

[0012] Step 3: After the temperature cycle mode is completed, the position error between the actual angle position and the expected angle position at each temperature is calculated, and the position error and temperature are nonlinearly fitted to obtain the mathematical relationship between the galvanometer angle and the temperature drift;

[0013] Step 4: Based on the mathematical relationship between temperature and position error obtained in step 3, temperature drift compensation for the galvanometer is realized.

[0014] Beneficial effects of the present invention:

[0015] 1. The present invention provides a device for measuring the actual positioning accuracy of the galvanometer movement angle affected by temperature. The optical cross hairs emitted by the theodolite pass through a high and low temperature box to reach the galvanometer. The actual angle position can be obtained by reading the center of the cross on the theodolite, thereby obtaining the angle error.

[0016] 2. The correlation between the actual angle and the measured angle provided by the present invention is a nonlinear relationship. A nonlinear fitting method is used to obtain the closest quadratic or cubic mathematical relationship for subsequent angle compensation.

[0017] 3. The present invention adds a temperature sensor inside the galvanometer, and can realize temperature compensation of the galvanometer body through the temperature value fed back by the temperature sensor and the relationship between the error and temperature obtained above, thus providing good input conditions for realizing the temperature compensation closed-loop strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0019] Figure 1 It is a structural schematic diagram of a device for measuring the temperature drift of the galvanometer motion angle according to the present invention;

[0020] Figure 2 The schematic diagram is a method for measuring the temperature drift of the galvanometer motion angle according to the present invention.

[0021] In the figure: 1. external power supply, 2. computer, 3. high and low temperature chamber, 4. air floating vibration isolation table, 5. temperature chamber window, 6. galvanometer body, 7. galvanometer control box, 8. theodolite, 9. power cord, 10. temperature sensor. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific implementation methods and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0023] Obviously, the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be noted that the terms “first”, “second” and “third” are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0025] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] The present invention will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, the same elements are represented by similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale.

[0027] Specific implementation method 1. Combination Figure 1 This embodiment describes a device for measuring the temperature drift of the galvanometer motion angle. In this device, the galvanometer has the advantages of high precision, large scanning angle, and fast response speed, and has been applied to the fields of precision laser processing, laser radar, and optical imaging. The galvanometer is one of the core components of the optical scanning system, and its scanning speed and accuracy are crucial. In actual engineering, the galvanometer deflection angle is easily affected by the external environment, and the temperature drift problem caused by the change of working environment temperature causes the angular position of the galvanometer to deviate.

[0028] The actual angle position of the galvanometer is based on the measurement result of the theodolite. At different temperatures, the angle measured by the galvanometer will change compared to the actual angle. The operating temperature range of the galvanometer application is very wide, usually -40℃ to +60℃. Measuring the change of the angle of the galvanometer under different temperature conditions is conducive to understanding the change law of angle accuracy, and on this basis, calibration and compensation can be performed, which can greatly improve the full-temperature angle accuracy of the galvanometer.

[0029] The device for measuring the temperature drift of the galvanometer angle provided by the present invention can measure the angle of the galvanometer at different temperatures, thereby finding out the variation law of its angle accuracy. By analyzing the measurement data, mathematical modeling is used to solve the nonlinear functional relationship between the actual angle of the galvanometer at different temperatures and the measured angle.

[0030] The device for measuring the temperature drift of the galvanometer motion angle described in this embodiment specifically includes a power supply 1, a computer 2, a high and low temperature box 3, an air-floating vibration isolation table 4, a temperature box window 5, a galvanometer body 6, a galvanometer control box 7, a theodolite 8, a power cord 9 and a temperature sensor 10;

[0031] The power supply 1 is used to power the galvanometer control box 7 and the galvanometer body 6. The galvanometer body 6 and the galvanometer control box 7 are located in the high and low temperature box 3, and the theodolite 8 is located outside the high and low temperature box 3, and both are located on the surface of the air-floating vibration isolation table 4 with the high and low temperature box 3, so as to isolate the interference caused by the external environment; the computer 2 is connected to the galvanometer control box 7 through an RS422 to USB connection cable, and the host computer software required by the galvanometer is installed inside the computer 2, which is used to control the galvanometer to the desired angle and transmit the real-time position to the host computer software to facilitate confirmation of whether it is in place.

[0032] In this embodiment, the high and low temperature box 3 and the air floating vibration isolation table 4 are integrated devices, which are used to isolate external vibrations and vibrations caused by the operation of the compressor inside the high and low temperature box 3, thereby eliminating the influence of external vibrations on the position accuracy of the galvanometer.

[0033] In this embodiment, the galvanometer body 6 and the galvanometer control box 7 belong to a complete set of galvanometer equipment (galvanometer system). The galvanometer control box 7 is powered by an external power supply 1, and then converts the SCI signal for external communication into a USB port that can be recognized by the computer, so as to realize position control by the host computer software installed on the computer, and controls the galvanometer to move to the command position through the host computer software installed inside the computer.

[0034] In this embodiment, a temperature sensor 10 is provided on the motor of the galvanometer body 6 for realizing temperature measurement. At the same time, since the motor is a heating mechanism in actual work, it is sensitive to temperature.

[0035] In this embodiment, the theodolite 8 is placed on the surface of the air-floating vibration isolation table 4, the mirror center of the galvanometer body 6 and the center of the visual axis of the theodolite 8 are located in the same plane, and the optical crosshairs emitted by the theodolite 8 pass through the high and low temperature box 3 to reach the galvanometer body 6. By reading the center of the crosshairs on the theodolite 8, the actual angular position at different temperatures can be obtained, thereby obtaining the angular error.

[0036] In this embodiment, 25°C is used as a reference, and a temperature box is configured to be set at intervals of 5°C. After reaching the temperature and keeping the temperature for 1 hour, the upper computer controls the galvanometer to move to a specified angle, starting from 0°, at intervals of ±0.5°, and ending at ±5°. The actual position information of the galvanometer body 6 is recorded by using the theodolite 8. The temperature and the actual movement angle of the galvanometer recorded by the theodolite 8 in the full temperature range are recorded in a table. Since the setting of the expected angle and the actual angle are in a nonlinear relationship, nonlinear fitting is adopted to obtain the position error by subtracting the setting of the expected angle from the actual angle and fit the relationship with the temperature into a quadratic or cubic relationship.

[0037] Specific implementation method 2: Combination Figure 2 This embodiment is described as a method of a device for measuring the temperature drift of the galvanometer motion angle described in the specific embodiment 1. The real-time calibration is carried out through the control box and the galvanometer body based on the mathematical relationship between the temperature and position error and the preset compensation strategy.

[0038] The galvanometer system responds to the desired angle value for the given angle control value and measures the current temperature. Through the mathematical relationship between temperature and position error, the current temperature value is input to obtain the position error, and the position error is converted into a relationship with the input angle. Finally, the correction amount for the given angle is obtained, and the correction amount is used as feedback to realize real-time correction of the position error.

[0039] The specific implementation steps are as follows:

[0040] 1. At room temperature of 25°C, place the galvanometer body 6 and the galvanometer control box 7 in the high and low temperature box 3, power on the galvanometer control box 7 through the external power supply 1, and convert the SCI signal for external communication into a USB port that can be recognized by the computer through the debugging cable, so as to realize position control by the host computer installed on the computer 2, and control the galvanometer body 6 to move to the command position through the host computer software installed inside the computer 2, such as the executable interface written by Visual Studio, QT, etc. Use the host computer software to set the initial angle to 0°, use the theodolite 8 to aim at the galvanometer body 6, and record the current position and current temperature. The temperature is displayed by the high and low temperature box window 5, and the temperature sensor 10 on the motor can also measure the current temperature.

[0041] 2. Within the full temperature range of the galvanometer body 6, set the high and low temperature box 3 to enter the temperature cycle mode, set a fixed temperature difference at each interval, and keep warm for one hour after reaching the temperature. Power on the galvanometer control box 7 through the external power supply 1, use the upper computer software to set the initial angle of the galvanometer to 0° and the interval to ±0.5°, use the theodolite 8 to aim at the galvanometer body 6, and record the actual angle position at that time, the given expected position and the current temperature.

[0042] 3. After the temperature cycle test, the temperature and position data are recorded in Table 1, with 25°C as the benchmark. The actual angle and expected angle corresponding to different angles at each temperature are recorded. The temperature value is recorded in the first column, the expected angle set by the computer is recorded in the second column, and the actual angle measured by the theodolite is recorded in the third column. The error between the third column and the second column is calculated to obtain the position error. The position error and temperature are used as inputs for data fitting to obtain a nonlinear curve. The curve may be a quadratic or cubic function. Thus, the mathematical relationship of the temperature drift of the galvanometer motion angle is obtained.

[0043] Table 1

[0044]

[0045]

[0046] 4. The mathematical relationship of the temperature drift of the galvanometer motion angle obtained in step 3 and the temperature sensor of the galvanometer can be used as the input of the temperature compensation control to realize the temperature drift compensation of the galvanometer.

[0047] In this embodiment, the galvanometer system responds to the desired angle value for a given angle control value and measures the current temperature. Through the mathematical relationship between temperature and position error, the current temperature value is input to obtain the position error, and the position error is converted into a relationship with the input angle, and finally the correction amount for the given angle is obtained. The correction amount is used as feedback to realize real-time correction of the position error.

[0048] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0049] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A device for measuring and correcting the temperature drift of the galvanometer motion angle, characterized in that: The device comprises an external power supply (1), a computer (2), a high and low temperature box (3), an air-floating vibration isolation table (4), a galvanometer body (6), a galvanometer control box (7) and a theodolite (8); The external power supply (1) is used to supply power to the galvanometer control box (7) and the galvanometer body (6); the galvanometer body (6) and the galvanometer control box (7) are located in a high-temperature and low-temperature box (3); the theodolite (8) is located outside the high-temperature and low-temperature box (3), and both the high-temperature and low-temperature box (3) and the galvanometer control box (7) are located on the surface of an air-floating vibration isolation table (4); the computer (2) is connected to the galvanometer control box (7) via an RS422 to USB connection cable; a host computer software is installed inside the computer (2) for controlling the movement angle of the galvanometer body and transmitting the real-time position to the host computer software.

2. The device for measuring and correcting the temperature drift of the galvanometer motion angle according to claim 1, characterized in that: A temperature sensor (10) is provided on the motor of the galvanometer body (6) for realizing temperature measurement.

3. The device for measuring and correcting the temperature drift of the galvanometer motion angle according to claim 2, characterized in that: The center of the mirror surface of the galvanometer body (6) and the center of the visual axis of the theodolite (8) are located in the same plane, and the real-time position under different temperatures is read by aiming the mirror surface of the galvanometer body (6) through the theodolite (8).

4. A method for measuring and correcting the temperature drift of the galvanometer motion angle, characterized in that: The method is implemented by a device for measuring and correcting the temperature drift of the galvanometer motion angle as described in any one of claims 1 to 3, and the method is implemented by the following steps: Step 1: Place the galvanometer body and the galvanometer control box in a high and low temperature box, send a control command to the galvanometer control box through the host computer, control the galvanometer body to move to the specified position, and set the initial angle of the galvanometer body to 0°; Step 2: Set the high and low temperature box to enter the temperature cycle mode, use the theodolite to aim at the galvanometer body, and record the current actual angle position, the given expected angle position energy and the current temperature; Step 3: After the temperature cycle mode is completed, the position error between the actual angle position and the expected angle position at each temperature is calculated, and the position error and temperature are nonlinearly fitted to obtain the mathematical relationship between the galvanometer angle and the temperature drift; Step 4: Based on the mathematical relationship between temperature and position error obtained in step 3, temperature drift compensation for the galvanometer is realized.

5. A method for measuring and correcting the temperature drift of the galvanometer motion angle according to claim 4, characterized in that: In step 1, the galvanometer control box is powered on by an external power supply, the SCI signal of the external communication is converted into a USB port signal recognized by the computer through a debugging cable, and the position of the galvanometer body is controlled by the host computer software installed on the computer.

6. The method for measuring and correcting the temperature drift of the galvanometer motion angle according to claim 4, characterized in that: In step 2, the temperature cycle mode of the high and low temperature box is set to: a fixed temperature difference at each interval, and after reaching the temperature, keep warm for one hour; the upper computer is used to control the galvanometer angle interval to ±0.5°.

7. A method for measuring and correcting the temperature drift of the galvanometer motion angle according to claim 4, characterized in that: In step 4, the galvanometer system responds to the desired angle value for the given angle control value and measures the current temperature. Through the mathematical relationship between temperature and position error, the current temperature value is input to obtain the position error, and the position error is converted into a relationship with the input angle. Finally, the correction amount for the given angle is obtained, and the correction amount is used as feedback to correct the position error in real time.

Images