Method for measuring angular acceleration of photoelectric turntable in inertial space

Abstract

The invention relates to the technical field of servo control, and particularly provides a method for measuring the angular acceleration of a photoelectric turntable in an inertial space, which is used for measuring the angular acceleration of the photoelectric turntable, and comprises the following steps: installing a plurality of groups of accelerometers on the photoelectric turntable, one group of accelerometers correspondingly measure the angular acceleration of one rotating shaft of the photoelectric turntable, each group of accelerometers consists of two accelerometers, sensitive axes of the two accelerometers are parallel to each other and are vertical to the rotating shaft, measured by the group of accelerometers, of the photoelectric turntable, and the photoelectric turntable is rotated around the measured rotating shaft; and acquiring output data corresponding to the two accelerometers, and calculating the angular acceleration of the photoelectric turntable rotating around the measured rotating shaft according to the output data. The method can adapt to photoelectric rotary tables of different sizes and shapes, and is high in universality and easy to implement.

Description

Technical Field

[0001] This invention relates to the field of servo control technology, specifically providing a method for measuring the angular acceleration of an optoelectronic turntable in inertial space. Background Technology

[0002] Domestic and international research has fully demonstrated that acceleration closed-loop control technology can effectively improve the ability of photoelectric tracking control systems to suppress external disturbances, suppress resonance phenomena, and broaden the system control bandwidth. In servo control systems without dedicated angular acceleration sensors, angular acceleration is typically acquired using methods such as angular acceleration observers, gyroscope differentials, or encoder differentials, and current mainstream angular acceleration measurement methods are based on this. However, these angle measurement-based methods have inherent drawbacks: observer methods usually have large delays, and differential operations amplify noise, making it difficult to meet the requirements of high-precision photoelectric tracking systems for suppressing external disturbances.

[0003] To overcome these shortcomings, several innovative angular acceleration measurement technologies have emerged in recent years. For example, Chinese patent publication number CN105259370A, published on January 20, 2016, entitled "An Angular Acceleration Measurement Device Based on MEMS Linear Accelerometers," includes two MEMS linear accelerometers arranged at the center and edge. During use, it is necessary to ensure that the central axis of the device is completely aligned with the axis of rotation being measured, which is difficult to achieve and results in large errors. Another example is Chinese patent publication number CN117782162A, published on March 29, 2024, entitled "A Turntable Angular Acceleration Testing Device and Method Based on Multiple Accelerometers." While its measurement method can significantly reduce delay and noise, it is still subject to limitations imposed by the working principle... Due to limitations in design and structural dimensions, there are strict requirements for installation location and limited output resolution. Chinese patent publication number CN115308436A, published on November 8, 2022, entitled "An Angular Acceleration Measurement Device Based on a Fiber Optic Sagnac Interferometer," while offering results with low delay, high accuracy, and high resolution, suffers from complex manufacturing processes and high costs. Chinese patent publication number CN115856353A, published on March 28, 2023, entitled "A Balanced Pendulum Structure, Angular Acceleration Measurement Device and Method," exhibits lower reliability compared to mainstream MEMS sensors. Therefore, a new angular acceleration measurement method is urgently needed that meets the requirements of low delay, high resolution, fewer installation constraints, and low cost. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for measuring angular acceleration on an inertial space photoelectric turntable. An accelerometer is installed on the photoelectric turntable in a specific manner, and the angular acceleration is calculated using the output data obtained from the accelerometer. This method is highly versatile and applicable to various photoelectric turntables.

[0005] The method for measuring the angular acceleration of an inertial space photoelectric turntable provided by this invention includes: S1: Install on the photoelectric turntable A group of accelerometers, among which, The value is the same as the number of rotating axes of the photoelectric turntable. One set of accelerometers measures the angular acceleration of one rotating axis of the photoelectric turntable. Each set of accelerometers consists of two accelerometers, with the sensitive axes of the two accelerometers parallel to each other and perpendicular to the rotation axis of the photoelectric turntable that is measured by the set of accelerometers. S2: Rotate the photoelectric turntable around the rotation axis being measured to obtain the output data of the corresponding two accelerometers; S3: Calculate the angular acceleration of the photoelectric turntable rotating about the axis of rotation being measured. for: ; in, and These represent the output data of the two accelerometers, This indicates the angular velocity of the photoelectric turntable rotating about the axis being measured. and These represent the distances between the two accelerometers and the corresponding rotation axes being measured. This represents the angle between the first line and the second line. The first line represents the angle between the second and third lines. The first line is the line connecting the first accelerometer and the measured rotation axis, and the first line is perpendicular to the measured rotation axis. The second line passes through the measured rotation axis, is parallel to the corresponding sensitive axis, and the plane containing the sensitive axis is perpendicular to the measured rotation axis. The third line is the line connecting the second accelerometer and the measured rotation axis, and the third line is perpendicular to the measured rotation axis.

[0006] Preferably, the accelerometer is a linear accelerometer.

[0007] Preferably, in S2, the output data of the two accelerometers are : ; in, This indicates the serial number of the accelerometer within each group. The value can be 1 or 2. Represents gravitational acceleration. This indicates the angle between the accelerometer's sensing axis and the direction perpendicular to the horizontal plane. This indicates the distance between the accelerometer's sensing axis and the corresponding rotational axis being measured.

[0008] Preferably, in S1, the photoelectric turntable is installed. Each group of accelerometers also satisfies either the first or the second limiting condition: First limiting condition: ; Second limiting condition: , .

[0009] Preferably, when the first limiting condition is met, the angular acceleration of the photoelectric turntable rotating about the axis of rotation being measured is... for: ; When the second limiting condition is met, the angular acceleration of the photoelectric turntable rotating about the axis of rotation being measured is... for: ; in, This indicates the distance between the two accelerometers.

[0010] Compared with the prior art, the present invention can achieve the following beneficial effects: The method of this invention uses two accelerometers for measuring a rotation axis, with the sensitive axes of the two accelerometers parallel to each other and perpendicular to the rotation axis. This configuration helps to directly and accurately capture the acceleration changes caused by rotation, and by comparing the outputs of the two accelerometers, sensor drift problems can be detected more easily. Since the sensitive axes of the two accelerometers are parallel, in practical applications, calibration time and cost can be reduced by calibrating the two accelerometers simultaneously. The calibration process can be more consistent and simplified, and the output data of the two accelerometers can be used for mutual verification and correction, thereby simplifying the signal processing process.

[0011] The method of this invention can be adapted to photoelectric turntables of different sizes and shapes. For photoelectric turntables with multiple rotation axes, the method of this invention can be easily extended to measure the angular acceleration of each rotation axis. It is highly versatile, applicable to various photoelectric turntables, and simple to implement.

[0012] Compared with the prior art, the angular acceleration formula calculated by the method of the present invention has a higher resolution because the denominator is the distance between the two accelerometers. Attached Figure Description

[0013] Figure 1 This is a flowchart of a photoelectric turntable angular acceleration measurement method in inertial space according to an embodiment of the present invention; Figure 2 This is a front view of a single-axis photoelectric turntable with two accelerometers installed, according to an embodiment of the present invention. Figure 3This is a top view of a single-axis photoelectric turntable with two accelerometers installed, according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the installation of a three-axis photoelectric turntable accelerometer according to an embodiment of the present invention; Figure 5 This is a measured step response curve of acceleration closed loop provided according to an embodiment of the present invention; Figure 6 This is a curve of sinusoidal guided tracking error data provided according to an embodiment of the present invention. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and do not constitute a limitation thereof. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0015] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined to form various implementations. Furthermore, the order of the steps or actions in the method description can be changed or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a mandatory order, unless otherwise stated that a particular order must be followed.

[0016] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0017] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0018] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] like Figure 1 As shown, this invention provides a method for measuring the angular acceleration of an optoelectronic turntable in inertial space, specifically including: S1: Install on the photoelectric turntable A group of accelerometers, among which, The value is the same as the number of rotation axes of the photoelectric turntable. One set of accelerometers measures the angular acceleration of one rotation axis of the photoelectric turntable. Each set of accelerometers consists of two accelerometers, and the sensitive axes of the two accelerometers are parallel to each other and perpendicular to the rotation axis of the photoelectric turntable that is measured by the set of accelerometers.

[0020] Different photoelectric turntables typically possess different degrees of freedom; therefore, they may include one or more rotational axes, such as single-axis photoelectric turntables, three-axis photoelectric turntables, etc. This embodiment of the invention measures the angular acceleration of a photoelectric turntable rotating about a specific rotational axis. Before measurement, a [device / structure] is installed on the photoelectric turntable. A group of accelerometers, among which, The value of ω is the same as the number of rotation axes of the photoelectric turntable. For example, when measuring the angular acceleration of a single-axis photoelectric turntable rotating around its rotation axis, only one set of accelerometers is needed. When measuring the angular acceleration of a three-axis photoelectric turntable rotating around its three rotation axes, three sets of accelerometers are required. Each set of accelerometers consists of two accelerometers, corresponding to the angular acceleration measured when the photoelectric turntable rotates around one rotation axis.

[0021] like Figure 2 and Figure 3 As shown, this embodiment of the invention uses a single-axis photoelectric turntable as an example. To measure the angular acceleration of the single-axis photoelectric turntable when it rotates around its rotation axis, a set of accelerometers (two accelerometers) needs to be installed. In this embodiment, they are referred to as the first accelerometer and the second accelerometer, and both the first and second accelerometers are linear accelerometers. The first and second accelerometers are installed on the single-axis photoelectric turntable, and the following conditions must be met during installation: the sensitive axes of the first and second accelerometers are parallel to each other, and both the sensitive axes of the first and second accelerometers are perpendicular to the rotation axis of the single-axis photoelectric turntable.

[0022] It should be noted that, as Figure 4 As shown, when the photoelectric turntable is a multi-axis photoelectric turntable, such as a three-axis photoelectric turntable, three sets of accelerometers need to be installed. Each set of accelerometers contains two accelerometers, for a total of six accelerometers. When measuring angular acceleration, each set of two accelerometers measures the angular acceleration around a rotation axis. Therefore, when installing the accelerometers, the sensitive axes of the two accelerometers in each set are parallel and perpendicular to the corresponding rotation axis to be measured. Consequently, the installation orientations of the six accelerometers are not the same.

[0023] S2: Rotate the photoelectric turntable around the rotation axis being measured to obtain the output data of the corresponding two accelerometers.

[0024] Continuing with the example of a single-axis photoelectric turntable, rotating the turntable allows us to acquire corresponding output data via two installed accelerometers. The output data from the two accelerometers are as follows: : ; in, This indicates the serial number of the accelerometer within each group. Each group contains two accelerometers: the first accelerometer and the second accelerometer. Therefore, The value can be 1 or 2, corresponding to the first accelerometer and the second accelerometer. Represents gravitational acceleration. This represents the angle between the sensitive axis of the accelerometer and the direction perpendicular to the horizontal plane. Since the sensitive axes of the first and second accelerometers are parallel, the angle between the first and second accelerometers is... The values ​​are the same. This indicates the distance between the accelerometer's sensing axis and the corresponding rotational axis being measured. This indicates the distance between the sensing axis of the first accelerometer and the corresponding rotational axis being measured. This indicates the distance between the sensing axis of the second accelerometer and the corresponding rotational axis being measured. This indicates the angular velocity of the photoelectric turntable rotating about the axis being measured. This represents the line connecting the accelerometer and the measured rotation axis, and this line is perpendicular to the measured rotation axis.

[0025] Since each group contains two accelerometers, namely the first accelerometer and the second accelerometer, the specific output results are as follows: ; ; in, This represents the output data of the first accelerometer. This indicates the output data of the second accelerometer. This represents the angle between the first line and the second line. The first line represents the angle between the second and third lines. The first line is the line connecting the first accelerometer and the measured rotation axis, and the first line is perpendicular to the measured rotation axis. The second line passes through the measured rotation axis, is parallel to the corresponding sensitive axis, and the plane containing the sensitive axis is perpendicular to the measured rotation axis. The third line is the line connecting the second accelerometer and the measured rotation axis, and the third line is perpendicular to the measured rotation axis.

[0026] It should be noted that when an accelerometer is working, the output result is a definite constant value. The formula corresponding to the above output data shows the calculation process for obtaining the constant value of the accelerometer output, which includes the gravitational acceleration component. Centripetal acceleration component angular acceleration components The angular acceleration component includes angular acceleration, so the angular acceleration can be obtained from this.

[0027] S3: Calculate the angular acceleration of the photoelectric turntable as it rotates around the axis being measured.

[0028] Based on the output data of the first and second accelerometers, calculate the angular acceleration of the photoelectric turntable rotating about the measured axis of rotation. for: .

[0029] Because the output data of the first and second accelerometers include a centripetal acceleration component. Therefore, the calculated angular acceleration is obtained. The expression also contains a centripetal acceleration component, which cannot be used as a feedback signal for acceleration closed-loop control and needs to be eliminated. This embodiment of the invention achieves the elimination of the centripetal acceleration component by imposing a restriction on the installation of an acceleration timer. The specific elimination method is as follows: In S1, an optical turntable is installed. In addition to restricting the sensitive axis of the accelerometers to have a direction, each group of accelerometers must also meet either a first or a second limiting condition. The first limiting condition is as follows: The second limiting condition is: ,and .

[0030] When the first limiting condition is met, the angular acceleration of the photoelectric turntable rotating about the axis of rotation being measured is... for: , in, This indicates the distance between the two accelerometers.

[0031] When the second limiting condition is met, the angular acceleration of the photoelectric turntable rotating about the axis of rotation being measured is... for: .

[0032] In summary, the two installed accelerometers satisfy the following conditions: the sensitive axes of the first and second accelerometers are parallel to each other, and both sensitive axes are perpendicular to the rotation axis of the single-axis photoelectric turntable. After satisfying either the first or second limiting condition, the angular acceleration of the photoelectric turntable rotating about the measured rotation axis can be finally obtained through the two accelerometers. for: .

[0033] When the photoelectric turntable being tested is a multi-axis photoelectric turntable, multiple sets of accelerometers are installed. Each set of accelerometers measures the angular acceleration of the photoelectric turntable rotating around one of its rotation axes, and finally obtains multiple angular accelerations.

[0034] The method of this invention has been used on a photoelectric turntable and has achieved closed-loop acceleration control (closed-loop bandwidth: 20Hz). The measured acceleration step response curve is shown below. Figure 5 As shown. The introduction of the acceleration closed loop significantly improves the photoelectric turntable control system's ability to suppress external disturbances. To verify the control effect of the acceleration closed loop, this invention conducted an outer frame sinusoidal guidance experiment, obtaining the following results. Figure 6The tracking error curve shown is between the classic three-loop control (TLS) and acceleration cascade control (AFC). Figure 6 It can be seen that the introduction of the acceleration closed loop greatly reduces the error spike during the turn and improves the overall tracking accuracy. Figure 6 In this context, "zero crossing" indicates a point of zero intersection, and "speed" indicates velocity. It represents angular error, which is essentially an angle.

[0035] Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0036] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for measuring the angular acceleration of an optoelectronic turntable in inertial space, characterized in that, include: S1: Installed on the photoelectric turntable A group of accelerometers, among which, The value is the same as the number of rotating axes of the photoelectric turntable, and a set of accelerometers measures the angular acceleration of one rotating axis of the photoelectric turntable. Each set of accelerometers consists of two accelerometers, and the sensitive axes of the two accelerometers are parallel to each other and perpendicular to the rotation axis of the photoelectric turntable that is measured by the set of accelerometers. S2: Rotate the photoelectric turntable around the rotation axis being measured to obtain the output data of the corresponding two accelerometers; S3: Calculate the angular acceleration of the photoelectric turntable rotating about the axis of rotation being measured. for: ； in, and These represent the output data of the two accelerometers, This indicates the angular velocity of the photoelectric turntable rotating about the axis of rotation being measured. and These represent the distances between the two accelerometers and the corresponding rotation axes being measured. This represents the angle between the first line and the second line. The first line represents the angle between the second and third lines. The first line is the line connecting the first accelerometer and the measured rotation axis, and the first line is perpendicular to the measured rotation axis. The second line passes through the measured rotation axis, is parallel to the corresponding sensitive axis, and the plane containing the sensitive axis is perpendicular to the measured rotation axis. The third line is the line connecting the second accelerometer and the measured rotation axis, and the third line is perpendicular to the measured rotation axis.

2. The method for measuring the angular acceleration of an inertial space photoelectric turntable as described in claim 1, characterized in that, The accelerometer is a linear accelerometer.

3. The method for measuring the angular acceleration of an inertial space photoelectric turntable as described in claim 1, characterized in that, In S2, the output data of the two accelerometers are : ； in, This indicates the serial number of the accelerometer within each group. The value can be 1 or 2. Represents gravitational acceleration. This indicates the angle between the accelerometer's sensing axis and the direction perpendicular to the horizontal plane. This indicates the distance between the accelerometer's sensing axis and the corresponding rotational axis being measured.

4. The method for measuring the angular acceleration of an inertial space photoelectric turntable as described in claim 1, characterized in that, In step S1, the photoelectric turntable is installed Each group of accelerometers also satisfies either the first or the second limiting condition: First limiting condition: ; Second limiting condition: , .

5. The method for measuring the angular acceleration of an inertial space photoelectric turntable as described in claim 4, characterized in that, When the first limiting condition is met, the angular acceleration of the photoelectric turntable rotating about the measured rotation axis is... for: ； When the second limiting condition is met, the angular acceleration of the photoelectric turntable rotating about the measured rotation axis is... for: ； in, This indicates the distance between the two accelerometers.

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