Precise control device and method for high-frequency angular vibration test bench

Abstract

The invention discloses a precision control device of a high-frequency angular vibration test stand, which comprises an angular vibration stand, a linear accelerometer, an air bearing, an angle encoder and a driving motor, a rotating shaft of a table top of the angular vibration table and a motor rotor of the driving motor are connected with an air bearing rotor of the air bearing, an air bearing stator of the air bearing and a motor stator of the driving motor are connected with the base, and the linear accelerometer is arranged on the upper portion of the angular vibration table and installed on the circumferential side of the table top. The central point of the linear accelerometer forms a reference circle relative to the midpoint of the table top, and the linear accelerometer is horizontally arranged, so that the central axis of the linear accelerometer coincides with one tangent line of the reference circle. Through closed-loop control of the linear accelerometer and position feedback of the absolute angle encoder, centering control of the high-frequency angular vibration table is achieved, the precision and distortion degree of angular acceleration are guaranteed, and precise control of high-frequency angular vibration is achieved.

Description

Technical Field

[0001] This invention relates to the field of angular vibration control, and in particular to a precision control device and method for a high-frequency angular vibration test bench. Background Technology

[0002] Angular vibration tables can generate sinusoidal angular vibration excitation and are mainly used for the calibration and standardization of angular vibration sensors and angular vibration measuring instruments. Currently, the market demand for high-frequency angular vibration tables is becoming increasingly urgent, but traditional testing equipment and control methods are insufficient to meet the accuracy and distortion requirements of high-frequency angular vibration angular acceleration.

[0003] Currently, conventional angular vibration tests typically operate at frequencies in the tens of Hz, yielding smooth angular acceleration sine curves at low frequencies. However, at high frequencies, the angular displacement approaches zero, and each measured angular displacement is extremely small. The control system must intervene with real-time adjustments to the angular acceleration, resulting in a sawtooth effect in the angular acceleration sine curve during high-frequency angular vibration, significantly reducing the accuracy and distortion of the angular acceleration readings. Furthermore, the frictional resistance caused by the preload of the shaft system has a significant impact on accuracy and distortion even with extremely small angular displacements.

[0004] Patent CN115540900A discloses a gyroscope frequency characteristic testing device and method based on sinusoidal signals. However, its structure is overly complex, and the angular vibration frequency shown in its graph is below 80Hz, classifying it as low-frequency angular vibration, which is easily achievable with conventional angular vibration equipment. Furthermore, it only provides a framework for implementing low-frequency angular vibration, neglecting the control accuracy and distortion of the angular vibration equipment itself. Patent CN104316077B discloses a real-time measurement system for the angular position information of an angular vibration table, proposing a system with high measurement accuracy and usability in harsh environments. However, this method is only applicable to external measurement and calibration of the angular vibration equipment by a third party, not for the control of the angular vibration itself; therefore, the control accuracy and distortion of the angular vibration table itself are also not considered. Summary of the Invention

[0005] Purpose of the invention: To address the above-mentioned problems, the purpose of this invention is to provide a precision control device and method for a high-frequency angular vibration test bench, thereby solving the problem of angular acceleration distortion in high-frequency angular vibration.

[0006] Technical solution: A precision control device for a high-frequency angular vibration test bench includes an angular vibration table, a linear accelerometer, an air bearing, and an angle encoder and a drive motor installed inside the base of the angular vibration table. The angle encoder is connected to the drive motor. The rotation axis of the angular vibration table and the motor rotor of the drive motor are respectively connected to the air bearing rotor of the air bearing. The air bearing stator of the air bearing and the motor stator of the drive motor are respectively connected to the base. The linear accelerometer is set on the upper part of the angular vibration table and is installed on the circumferential side of the table. Its center point forms a pitch circle with respect to the midpoint of the table. The linear accelerometer is set horizontally so that its central axis coincides with one of the tangents of the pitch circle.

[0007] Furthermore, the radius of the pitch circle is R, the linear acceleration value measured by the linear accelerometer is a, and the angular acceleration of the vibration test bench is obtained.

[0008] Furthermore, the platform is circular, with a flat surface cut into its outer circumference. The sensor mounting base is fixed to the flat surface by screws, and the linear accelerometer is connected to the sensor mounting base by positioning studs.

[0009] Furthermore, the angle encoder is an open-type angle encoder, including an encoder grating and an encoder reading head. The encoder grating is connected to the motor rotor, and the encoder reading head is fixed to the motor stator through a reading head bracket.

[0010] Ideally, the drive motor should be a separate direct-drive motor.

[0011] Ideally, the device also includes a control system, which includes a controller, a preamplifier module, and a driver connected in sequence. The driver controls the drive motor of the angular vibration table, the angle encoder transmits the signal to the controller through the driver, and the linear accelerometer transmits the angular acceleration signal to the controller.

[0012] A control method for the precision control device of the above-mentioned high-frequency angular vibration test bench includes the following steps:

[0013] Step 1: Set the frequency and angular acceleration requirements on the controller software. The controller then sends an angular acceleration operation command to the front-end module. The front-end module processes the angular acceleration command and converts it into an angular velocity command, which is then sent to the driver. The driver adjusts the drive voltage to make the drive motor perform angular vibration motion.

[0014] Step 2: The angle encoder and linear accelerometer work. The angle encoder provides real-time feedback of the angular position and provides the absolute zero position to the controller. The angle encoder provides real-time feedback of the current position. The controller performs centering control through the absolute zero position diagonal vibration table, so that its sinusoidal vibration always works at the zero position.

[0015] Step 3: The linear accelerometer transmits the obtained smooth angular acceleration sine curve to the controller through conversion, forming a closed-loop control.

[0016] This invention sends an angular acceleration operation command to the front-end module via a controller. The front-end module converts the angular acceleration command into an angular velocity command and sends it to the driver. The driver then drives the motor to perform angular vibration.

[0017] Beneficial effects: Compared with the prior art, the advantages of the present invention are: The angular vibration table of the present invention is equipped with an absolute angle encoder to provide real-time feedback on the angular position. The controller performs centering control on the angular vibration table through the absolute zero position, so that its sinusoidal vibration, sweep frequency vibration and other working modes always work at the zero position, preventing its drift and over-displacement.

[0018] A linear accelerometer is used for closed-loop control to ensure the accuracy and distortion of angular acceleration during angular vibration. The linear accelerometer is tangentially mounted on the outer side of the angular vibration table, and the mounting radius is recorded. The linear acceleration is converted into angular acceleration using a formula and fed back to the controller for closed-loop control.

[0019] The motor is a direct-drive motor with separate rotor and stator, the angle encoder is an open encoder with grating and reading head, and the shaft system uses air bearings. By adopting a separate structure for all components, the fixed and moving parts of the entire system are kept in contact, improving the accuracy and distortion of angular vibration.

[0020] This invention ensures the accuracy and distortion of angular vibration angular acceleration, as well as zero-position alignment, through the above four aspects. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention;

[0022] Figure 2 This is a top view of the present invention;

[0023] Figure 3 Schematic diagram of linear accelerometer installation;

[0024] Figure 4 This is a flowchart of the high-frequency control signal transmission process for an angular vibration table.

[0025] Figure 5 A schematic diagram of a sawtooth-shaped angular acceleration sinusoidal waveform;

[0026] Figure 6 This is a schematic diagram of the sinusoidal waveform of angular acceleration. Detailed Implementation

[0027] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0028] A precision control device for a high-frequency angular vibration test bench, such as Figures 1-6 As shown, the device includes an angular vibration table 100, a control system, an angle encoder, and a linear accelerometer 8. The angle encoder is located at the lower part of the angular vibration table 100 and is installed inside the base 4 of the angular vibration table 100. Its stator is fixed to the base 4, and its rotor is connected to the rotation shaft 3 of the angular vibration table 100. The angle encoder is an absolute angle encoder.

[0029] The system includes an angular vibration table 100, a linear accelerometer 8, a control system, an air bearing, and an angle encoder and a drive motor 500 installed inside the base 4 of the angular vibration table 100. The angle encoder is connected to the drive motor 500 and is an open-type angle encoder. During the operation of the angular vibration table 100, it provides precise real-time angular position feedback and performs centering control through its absolute zero position. The angle encoder includes an encoder grating 12 and an encoder reading head 13. The encoder grating 12 is connected to the motor rotor 501 of the drive motor 500, and the encoder reading head 13 is fixed to the motor stator 502 of the drive motor 500 through a reading head bracket 14.

[0030] The drive motor 500 is a split direct drive motor. The rotation shaft of the table 1 of the angular vibration table 100 and the motor rotor 501 of the drive motor 500 are respectively connected to the air bearing rotor 2 of the air bearing. The air bearing stator 3 of the air bearing and the motor stator 502 of the drive motor 500 are respectively connected to the base 4. The linear accelerometer 8 is set on the upper part of the angular vibration table 100. The linear accelerometer 8 is installed on the circumferential side of the table 1, and its center point forms a pitch circle 5 with respect to the midpoint of the table 1. The linear accelerometer 8 is set horizontally so that its central axis 3 coincides with one of the tangents 6 of the pitch circle 5.

[0031] The linear accelerometer 8 is located on the upper part of the angular vibration table 100. The linear accelerometer 8 is installed on the circumferential side of the table surface 1 of the angular vibration table 100. Its center point forms a pitch circle 5 with respect to the midpoint of the table surface 1. The linear accelerometer 8 is set horizontally so that its central axis 3 coincides with one of the tangents 6 of the pitch circle 5.

[0032] To ensure shaft system accuracy, conventional shaft systems employ large preloads to achieve high precision. However, the rotational resistance of the bearings significantly impacts the accuracy and distortion of angular acceleration. Therefore, this invention utilizes air bearings, eliminating bearing frictional resistance while maintaining shaft rotational accuracy. Similarly, a split-type direct-drive motor, with its rotor directly connected to the bearing rotor, and an open encoder are used to further reduce frictional resistance. Through this combination of air bearings, a split-type direct-drive motor, and an open encoder, the angular vibration shaft system achieves frictionless operation, laying a mechanical foundation for precise and distortion-free angular acceleration.

[0033] The platform 1 is circular, and a flat surface 11 is cut on its outer circumference. The sensor mounting base 7 is fixed to the flat surface 11 by screws and is in close contact with it. The linear accelerometer 8 is connected to the sensor mounting base 7 by positioning studs 9.

[0034] When installing the linear accelerometer 8, its axis 3 must coincide with the tangent 6 of the pitch circle 5. The radius R of the pitch circle 5 where the linear accelerometer 8 is located is obtained from the installation dimensions.

[0035] By finely adjusting the position of the positioning stud 9, it is ensured that the central axis 3 of the linear accelerometer 8 coincides with the tangent 6 of the pitch circle 5 where it is installed, and the accuracy of the radius R of the pitch circle 5 where the linear accelerometer 8 is installed is also guaranteed. This further ensures that the linear acceleration measured by the linear accelerometer can be accurately converted into angular acceleration.

[0036] In a linear vibration table, the direction of the linear accelerometer simply switches between forward and reverse. However, in an angular vibration environment, the direction of the linear accelerometer changes in real time, and the value is a sinusoidal curve. But the working principle of a linear accelerometer is to read the peak-to-peak value within one period, regardless of its direction vector. Therefore, in this device, the linear acceleration value measured by linear accelerometer 8 is 'a', and its angular acceleration 'α' can be calculated using the radius R.

[0037] Then angular acceleration

[0038] In the formula: α—angular acceleration converted by the linear accelerometer, in rad / s 2 ;

[0039] a — Linear acceleration measured by a linear accelerometer, in m / s² 2 ;

[0040] R—Radius of the scale circle where the linear accelerometer is installed, in meters (m).

[0041] Since the angular acceleration is the same at any position on the platform 1, the angular acceleration of the angular vibration table is measured as α by the linear accelerometer 8.

[0042] The control system includes a controller 200, a pre-module 300, and a driver 400 connected in sequence. The driver 400 controls the drive motor 500 of the angular vibration table 100. The angle encoder transmits the signal to the controller 200 through the driver 400, and the linear accelerometer 8 transmits the angular acceleration signal to the controller 200.

[0043] The control method of the precision control device for the aforementioned high-frequency angular vibration table includes the following steps:

[0044] Step 1: Set the frequency and angular acceleration requirements on the controller software. The controller then sends an angular acceleration operation command to the front-end module. The front-end module processes the angular acceleration command and converts it into an angular velocity command, which is then sent to the driver. The driver adjusts the drive voltage to make the drive motor perform angular vibration motion.

[0045] Step 2: The angle encoder and linear accelerometer work. The angle encoder provides real-time feedback of the angular position and provides the absolute zero position to the controller. The angle encoder provides real-time feedback of the current position. The controller performs centering control through the absolute zero position diagonal vibration table, so that its sinusoidal vibration always works at the zero position.

[0046] Step 3: The linear accelerometer transmits the obtained smooth angular acceleration sine curve to the controller through conversion, forming a closed-loop control.

[0047] An absolute angle encoder is installed inside the angular vibration table, which can not only provide real-time feedback of angular position but also provide an absolute zero position. During angular vibration, the encoder provides real-time feedback of the current position, and the controller uses the absolute zero position to center the angular vibration table, ensuring that its sinusoidal vibration always operates at the zero position, preventing drift and over-displacement.

[0048] This invention employs a linear accelerometer for closed-loop control. Linear accelerometers offer advantages such as high precision and high bandwidth, and can obtain a smooth angular acceleration sine curve, ensuring the accuracy and distortion of angular acceleration. The linear accelerometer is tangentially mounted on the outer side of the angular vibration table surface. Linear acceleration is converted into angular acceleration using a formula, and this converted is fed back to the controller for closed-loop control.

[0049] This invention achieves centering control of a high-frequency angular vibration table through closed-loop control of a linear accelerometer and position feedback of an absolute angle encoder, while ensuring the accuracy and distortion of angular acceleration, thus realizing precise control of high-frequency angular vibration.

Claims

1. A precision control device for a high-frequency angular vibration test bench, comprising an angular vibration table (100), characterized in that: It also includes a linear accelerometer (8), an air bearing, and an angle encoder and a drive motor (500) installed inside the base (4) of the angular vibration table (100). The angle encoder is connected to the drive motor (500). The rotation shaft of the table surface (1) of the angular vibration table (100) and the motor rotor (501) of the drive motor (500) are respectively connected to the air bearing rotor (2) of the air bearing. The air bearing stator (3) of the air bearing and the motor stator (502) of the drive motor (500) are respectively connected to the base (4). The linear accelerometer (8) is set on the upper part of the angular vibration table (100). The linear accelerometer (8) is installed on the circumferential side of the table surface (1). Its center point forms a pitch circle (5) with respect to the midpoint of the table surface (1). The linear accelerometer (8) is set horizontally so that its central axis (3) coincides with one of the tangents (6) of the pitch circle (5).

2. The precision control device for a high-frequency angular vibration test bench according to claim 1, characterized in that: The radius of the pitch circle (5) is R, the linear acceleration value measured by the linear accelerometer (8) is a, and the angular acceleration of the vibration test bench (100) is obtained.

3. The precision control device for a high-frequency angular vibration test bench according to claim 1, characterized in that: The platform (1) is circular, and a flat surface (11) is cut on its outer circumferential side. The sensor mounting base (7) is fixed to the flat surface (11) by screws. The linear accelerometer (8) is connected to the sensor mounting base (7) by positioning studs (9).

4. The precision control device for a high-frequency angular vibration test bench according to claim 1, characterized in that: The angle encoder is an open angle encoder, including an encoder grating (12) and an encoder reading head (13). The encoder grating (12) is connected to the motor rotor (501), and the encoder reading head (13) is fixed to the motor stator (502) through the reading head bracket (14).

5. The precision control device for a high-frequency angular vibration test bench according to claim 1, characterized in that: The drive motor (500) is a split direct drive motor.

6. The precision control device for a high-frequency angular vibration test bench according to claim 1, characterized in that: It also includes a control system, which includes a controller (200), a pre-module (300), and a driver (400) connected in sequence. The driver (400) controls the drive motor (500) of the angular vibration table (100). The angle encoder transmits the signal to the controller (200) through the driver (400), and the linear accelerometer (8) transmits the angular acceleration signal to the controller (200).

7. A control method for the precision control device of the high-frequency angular vibration test bench as described in claim 6, characterized in that... Includes the following steps: Step 1: Set the frequency and angular acceleration requirements on the controller software. The controller then sends an angular acceleration operation command to the front-end module. The front-end module processes the angular acceleration command and converts it into an angular velocity command, which is then sent to the driver. The driver adjusts the drive voltage to make the drive motor perform angular vibration motion. Step 2: The angle encoder and linear accelerometer work. The angle encoder provides real-time feedback of the angular position and provides the absolute zero position to the controller. The angle encoder provides real-time feedback of the current position. The controller performs centering control through the absolute zero position diagonal vibration table, so that its sinusoidal vibration always works at the zero position. Step 3: The linear accelerometer transmits the obtained smooth angular acceleration sine curve to the controller through conversion, forming a closed-loop control.

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