A telescope control system and an accelerometer sensor installation method based thereon

Abstract

The present invention relates to the technical field of ground-based large-aperture optical telescope control, and in particular to a telescope control system and an accelerometer sensor installation method based thereon; the present invention adds an acceleration feedback control loop to a double closed-loop control architecture based on a position loop and a velocity loop to form a three-closed-loop control architecture, and acquires angular acceleration information in the direction of a sensitive axis of the telescope by reasonably installing a plurality of accelerometers, thereby obtaining an accurate angular acceleration signal in the direction of the sensitive axis of the telescope, thereby providing acceleration information with a high signal-to-noise ratio for acceleration feedback closed-loop control, and further improving the tracking accuracy of the telescope under complex disturbance conditions; and by symmetrically installing more than two flexible linear accelerometers on the rotation of the telescope, the angular acceleration signal of the rotating axis can be accurately measured, thereby providing feedback information for realizing the acceleration closed-loop control of the control system.

Description

Technical Field

[0001] The invention relates to the technical field of ground-based large-aperture optical telescope control, and in particular to a telescope control system and an accelerometer sensor installation method based thereon. Background Art

[0002] The control system of ground-based large-aperture optical telescopes is usually designed with a dual closed-loop control architecture based on a position loop and a velocity loop. In fact, during operation, large-aperture optical telescopes will be affected by strong wind disturbances, shaft friction torque, and mechanical structure shaking, resulting in large tracking jitters when tracking targets, which in turn affects the stable imaging quality of the telescope.

[0003] Generally, the anti-disturbance capability of the control system of a ground-based large-aperture telescope under complex system disturbance conditions is based on a dual closed-loop control architecture of a position loop and a velocity loop. However, it is greatly affected by external factors such as strong wind load disturbances, shaft friction torque, and mechanical structure shaking. It can only obtain feedback of position and velocity information, but not acceleration information. Summary of the invention

[0004] The main technical problem solved by the present invention is to provide a telescope control system, which obtains angular acceleration information in the sensitive axis direction of the telescope through an acceleration feedback control loop, thereby obtaining an accurate angular acceleration signal in the sensitive axis direction of the telescope, thereby providing acceleration information with a high signal-to-noise ratio for acceleration feedback closed-loop control, thereby improving the tracking accuracy of the telescope under complex disturbance conditions; and also provides an accelerometer sensor installation method based on a telescope control system.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide a telescope control system, which includes a three-closed-loop control feedback mode structure, wherein the three-closed-loop control feedback mode structure includes a position control loop, a speed control loop and an acceleration control loop, and the feedback information of the acceleration control loop is provided by the angular acceleration signal feedback of the sensitive axis direction of the telescope detected by two or more accelerometer sensors installed on the rotating axis of the telescope.

[0006] As an improvement of the present invention, three accelerometer sensors are evenly distributed on the rotation axis of the telescope.

[0007] As a further improvement of the present invention, four accelerometer sensors are evenly distributed on the rotation axis of the telescope.

[0008] As a further improvement of the present invention, two accelerometer sensors are symmetrically mounted on the rotation axis of the telescope.

[0009] As a further improvement of the present invention, the accelerometer sensor adopts a flexible linear accelerometer.

[0010] As a further improvement of the present invention, the angular acceleration in the direction of the sensitive axis of the telescope is detected by first measuring the vector angular acceleration of the rotation axis, and then performing orthogonal decomposition to obtain the angular acceleration in the direction of the sensitive axis and the angular acceleration perpendicular to the direction of the sensitive axis, thereby obtaining the angular acceleration component in the direction of the sensitive axis and the angular acceleration of the rotation axis.

[0011] As a further improvement of the present invention, feedback information of the position control loop is provided by feedback of a position controller installed on the telescope.

[0012] As a further improvement of the present invention, feedback information of the speed control loop is provided by feedback of a speed controller installed on the telescope.

[0013] The beneficial effect of the present invention is as follows: compared with the prior art, the present invention adds an acceleration feedback control loop to a dual closed-loop control architecture based on a position loop and a velocity loop to form a three-closed-loop control architecture, and acquires angular acceleration information in the sensitive axis direction of the telescope by reasonably installing multiple accelerometers, thereby obtaining an accurate angular acceleration signal in the sensitive axis direction of the telescope, thereby providing acceleration information with a high signal-to-noise ratio for acceleration feedback closed-loop control, thereby improving the tracking accuracy of the telescope under complex disturbance conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the control architecture of the present invention;

[0015] Figure 2 Schematic diagram of measuring angular acceleration using a flexible linear accelerometer;

[0016] Figure 3 This is a schematic diagram of measuring angular acceleration in Example 1;

[0017] Figure 4 This is a schematic diagram of measuring angular acceleration in Embodiment 2;

[0018] Figure 5 This is a schematic diagram of measuring angular acceleration in Example 3. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] The present invention originally intended to add an acceleration feedback control loop to the dual closed-loop control architecture based on the position loop and the velocity loop, and obtain the angular acceleration signal in the direction of the telescope's sensitive axis by reasonably installing multiple accelerometers, thereby providing acceleration information with a high signal-to-noise ratio for the acceleration feedback closed-loop control, thereby improving the tracking accuracy of the telescope under complex disturbance conditions.

[0021] However, when performing acceleration feedback control of the telescope system, the problem encountered is how to accurately detect the angular acceleration signal in the direction of the telescope's sensitive axis, because the traditional angular acceleration signal detection method is to use a flexible linear accelerometer for detection, but the signal detected by this accelerometer sensor will be mixed with the components of gravity vector acceleration and disturbance acceleration, resulting in the inability to accurately obtain the effective signal required for acceleration feedback control, and ultimately leading to the failure of acceleration closed-loop control. Specifically, when a single flexible linear accelerometer measures the angular acceleration in the direction of the telescope's sensitive axis, the acceleration signal obtained is mixed with the components of gravity vector acceleration and disturbance acceleration, resulting in the inability to accurately detect the effective signal required for acceleration feedback control.

[0022] Therefore, please refer to Figures 1 to 5 The present invention provides a telescope control system, including a three-closed-loop control feedback mode structure, the three-closed-loop control feedback mode structure includes a position control loop, a speed control loop and an acceleration control loop, the feedback information of the acceleration control loop is provided by the angular acceleration signal feedback of the sensitive axis direction of the telescope detected by two or more accelerometer sensors installed on the rotating axis of the telescope, the feedback information of the position control loop is provided by the feedback of the position controller installed on the telescope, and the feedback information of the speed control loop is provided by the feedback of the speed controller installed on the telescope.

[0023] In the present invention, an acceleration feedback control loop is added to a dual closed-loop control architecture based on a position loop and a velocity loop to form a three-closed-loop control architecture. By reasonably installing multiple accelerometers to obtain angular acceleration information in the sensitive axis direction of the telescope, an accurate angular acceleration signal in the sensitive axis direction of the telescope is obtained, thereby providing acceleration information with a high signal-to-noise ratio for the acceleration feedback closed-loop control, thereby improving the tracking accuracy of the telescope under complex disturbance conditions.

[0024] Among them, the accelerometer sensor adopts a flexible linear accelerometer, which has the advantages of high stability, good repeatability, and strong environmental adaptability. Its output current is linearly related to the force or acceleration it receives. Therefore, the purpose of detecting the acceleration of the system can be achieved by selecting a suitable sampling resistor. Specifically, Figure 2 As shown, a flexible linear accelerometer is used to measure angular acceleration. The angular acceleration in the direction of the rotation axis is expressed as:

[0025]

[0026] Among them, a is the angular acceleration in the tangential direction of the rotation axis, r is the rotation radius of the accelerometer installation, and a is the linear acceleration in the tangential direction.

[0027] The present invention provides three embodiments. Embodiment 1 includes a three-closed-loop control feedback structure, which includes a position control loop, a speed control loop and an acceleration control loop. Feedback information of the acceleration control loop is provided by angular acceleration signal feedback in the sensitive axis direction of the telescope detected by two accelerometer sensors symmetrically installed on the rotating axis of the telescope. Specifically, Figure 3 As shown in the figure, two identical accelerometers A and B are symmetrically mounted on both sides of the rotation axis. Figure 2 The angular acceleration detection method shown in the figure measures the vector angular acceleration of the rotating axis as a A and a B , the two are equal in magnitude and opposite in sign; assuming that the angular acceleration being disturbed is a Dis , the acceleration is decomposed orthogonally, and the angular acceleration in the direction of the acceleration sensitive axis A and B is a DY , the angular acceleration in the direction perpendicular to the sensitive axes of acceleration A and B is a DX Therefore, the method of installing two accelerometers in opposite diameters can detect the angular acceleration component a in the direction of the acceleration sensitive axis A and B. DY , the sensitive axis of the accelerometer A is defined as the positive direction of the angular acceleration vector, so the angular acceleration of the rotation axis is expressed as:

[0028]

[0029] Among them, a AB is the angular acceleration of the rotation axis detected by accelerometers A and B.

[0030] The angular velocity of the disturbance is a Dis Angular acceleration component a in the direction of the acceleration sensitive axis A and B DY It is expressed as:

[0031]

[0032] It can be seen from expression (2) that the method of installing two accelerometers on the opposite diameter of the rotating shaft can improve the signal-to-noise ratio of angular acceleration detection while eliminating the influence of disturbance acceleration.

[0033] Embodiment 2 includes adopting a three-closed-loop control feedback structure, which includes a position control loop, a speed control loop and an acceleration control loop. The feedback information of the acceleration control loop is provided by the angular acceleration signal feedback of the sensitive axis direction of the telescope detected by four accelerometer sensors evenly distributed and installed on the rotating axis of the telescope. Specifically, Figure 4 As shown in the figure, four identical accelerometers A, B, C and D are installed 90° symmetrically in the tangent direction of the rotation axis. Figure 2 The angular acceleration detection method shown in the figure measures the vector angular acceleration of the rotating axis as a A 、a B 、a C and a D , where a A and a B The two are equal in magnitude and opposite in sign, where a C and a D The two are equal in magnitude and opposite in sign. The angular acceleration that is still disturbed is a Dis , the acceleration is decomposed orthogonally, and the angular acceleration in the direction of the acceleration sensitive axis A and B is a DY , the angular acceleration in the direction perpendicular to the sensitive axes of acceleration A and B is a DX Therefore, the method of installing two accelerometers in opposite diameters can detect the angular acceleration component a in the direction of the acceleration sensitive axis A and B. DY The angular acceleration component a in the direction of the acceleration sensitive axis C and D can be detected by installing two other accelerometers in opposite diameters. DX , therefore, the angular acceleration of the rotation axis is expressed as:

[0034]

[0035] Among them, a ABCD is the angular acceleration of the rotation axis detected by four accelerometers A, B, C and D.

[0036] The angular velocity of the disturbance is a Dis Angular acceleration component a in the direction of the acceleration sensitive axis A and B DY It is expressed as:

[0037]

[0038] The angular velocity of the disturbance is a Dis Angular acceleration component a in the direction of the acceleration sensitive axis C and D DX It is expressed as:

[0039]

[0040] It can be seen from expression (4) that compared with the installation method of two accelerometers, the method of installing four accelerometers on the opposite diameter of the rotating shaft can improve the signal-to-noise ratio of angular acceleration detection by 2 times while eliminating the influence of disturbance acceleration. In addition, it can also accurately detect the disturbance angular acceleration a Dis The weight of a DY and a DX .

[0041] Embodiment 3 includes adopting a three-closed-loop control feedback structure, which includes a position control loop, a speed control loop and an acceleration control loop. The feedback information of the acceleration control loop is provided by the angular acceleration signal feedback of the sensitive axis direction of the telescope detected by three accelerometer sensors evenly distributed and installed on the rotating axis of the telescope. Specifically, Figure 5 As shown in the figure, three identical accelerometers A, B, and C are installed 120° symmetrically in the tangent direction of the rotation axis. Figure 2 The angular acceleration detection method shown in the figure measures the vector angular acceleration of the rotating axis as a A 、a B 、a C , the angular acceleration still disturbed at this time is a Dis , the acceleration is decomposed orthogonally, and the angular acceleration in the direction of the acceleration sensitive axis A and B is a DY , the angular acceleration in the direction perpendicular to the sensitive axes of acceleration A and B is a DX , define the accelerometer C sensitive axis as the positive direction of the angular acceleration vector, and use the orthogonal decomposition method to obtain the angular acceleration of the rotation axis:

[0042]

[0043] The angular velocity of the disturbance is a Dis The angular acceleration component a in the direction perpendicular to the acceleration C sensitive axis DY It is expressed as:

[0044]

[0045] The angular velocity of the disturbance is a Dis Angular acceleration component a in the direction of the acceleration C sensitive axis DX It is expressed as:

[0046]

[0047] It can be seen from expression (7) that, compared with the installation method of two accelerometers, the method of installing three accelerometers symmetrically on the rotation axis can further improve the signal-to-noise ratio of angular acceleration detection while eliminating the influence of disturbance acceleration; in addition, it can also accurately detect the disturbance angular acceleration a DisThe weight of a DY and a DX ,However, compared to the installation of four accelerometers, the method of symmetrically installing three accelerometers improves the signal-to-noise ratio to a lower extent.

[0048] By symmetrically installing two or more flexible linear accelerometers in the direction of the sensitive axis of the telescope rotation, the angular acceleration signal of the rotation axis can be accurately measured, thereby providing feedback information for realizing the acceleration closed-loop control of the control system; from the comparison between Example 1 and Example 3, it can be seen that:

[0049] 1. If the solution of installing two accelerometers in opposite directions (Example 1) is selected, the advantage of this solution is that the installation is relatively simple, but the disadvantage is that the disturbance acceleration signal perpendicular to the installation direction of the accelerometer cannot be measured;

[0050] 2. If the solution of symmetrically installing four accelerometers is selected (Example 2), the advantage of this solution is that the signal-to-noise ratio of the detected angular acceleration signal is high, and the disturbance acceleration signal in the accelerometer installation direction and the vertical accelerometer installation direction can be measured simultaneously; the disadvantage of this solution is that the number of accelerometers is large and the installation requirements are high;

[0051] 3. If the solution of symmetrically installing three accelerometers is selected (Example 3), this solution is a compromise between the two accelerometer installation solution and the four accelerometer installation solution. It has a higher angular acceleration signal-to-noise ratio and can also simultaneously measure the disturbance acceleration signals in the accelerometer installation direction and the perpendicular accelerometer installation direction.

[0052] Therefore, when applying, you can choose from the above three embodiments according to actual needs.

[0053] The above description is only an implementation mode of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A telescope control system, characterized in that: The invention comprises adopting a three-closed-loop control feedback mode structure, wherein the three-closed-loop control feedback mode structure comprises a position control loop, a speed control loop and an acceleration control loop, wherein feedback information of the acceleration control loop is provided by feedback of angular acceleration signals in the sensitive axis direction of the telescope detected by two or more accelerometer sensors installed on the rotating axis of the telescope; Three or four accelerometer sensors are evenly distributed on the rotation axis of the telescope; the accelerometer sensor adopts a flexible linear accelerometer; The angular acceleration in the sensitive axis direction of the telescope is detected by first measuring the vector angular acceleration of the rotation axis, and then performing orthogonal decomposition to obtain the angular acceleration in the sensitive axis direction and the angular acceleration perpendicular to the sensitive axis direction, thereby obtaining the angular acceleration component in the sensitive axis direction and the angular acceleration of the rotation axis; Feedback information of the position control loop is provided by feedback from a position controller mounted on the telescope; Feedback information of the speed control loop is provided by feedback of a speed controller mounted on the telescope; Two or more flexible linear accelerometer sensors are evenly distributed and installed on the rotation axis of the telescope.

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