Five-degree-of-freedom active vibration isolation system
By installing seismographs and inclinometers on passive vibration isolators, and combining them with voice coil motors and main control computers, five independent vibration suppression control loops are constructed. This solves the problem that existing technologies cannot independently control vibrations of each degree of freedom, and achieves efficient suppression of five-degree-of-freedom vibrations and vibration isolation of precision instruments.
Patent Information
- Application Number
- CN202510932613.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-07
- Publication Date
- 2025-11-14
AI Technical Summary
Existing multi-degree-of-freedom active vibration isolation systems cannot achieve independent control of vibration in each degree of freedom, resulting in the inability to achieve targeted vibration suppression and stability compensation.
Design a five-degree-of-freedom active vibration isolation system. By setting up a seismograph and inclinometer on the passive vibration isolator, and combining them with a voice coil motor and a main control computer, five independent vibration suppression control loops are constructed to monitor and suppress linear vibrations in the x, y, and z directions, as well as angular vibrations along the x and y axes.
It achieves efficient suppression of five-degree-of-freedom vibrations and provides vibration isolation for precision instruments.
Smart Images
Figure CN120946735A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of precision vibration isolation technology, specifically relating to a five-degree-of-freedom active vibration isolation system. Background Technology
[0002] External vibration and noise in the working environment are among the main limiting factors for ultra-precision measuring instruments and manufacturing machines. Passive vibration isolators can only suppress vibrations with frequencies greater than √2 of their natural frequency, and cannot achieve a high suppression rate for low-frequency vibrations, which are of great significance for both ultra-precision instruments and ultra-precision machining. Adding active vibration isolation units to passive vibration isolators and applying feedback forces through active vibration isolation actuators to reduce low-frequency vibrations has become an effective method.
[0003] Active vibration isolation systems require the acquisition of vibrations in the direction to be suppressed. A controller then generates control signals based on these vibration signals, which are output to the actuators to suppress the vibrations. Current multi-degree-of-freedom active vibration isolation system designs must consider the coupling effect of the control output on the suppression of vibrations in different degrees of freedom, making independent control of each degree of freedom impossible. Consequently, targeted vibration suppression and stability compensation are not feasible. Therefore, designing a system capable of suppressing multi-degree-of-freedom vibrations, where each degree of freedom constitutes an independent control loop, is one of the key problems urgently needing to be solved in this field. Summary of the Invention
[0004] In view of the above-mentioned shortcomings in the prior art, the purpose of this invention is to provide a five-degree-of-freedom active vibration isolation system, which enables each degree of freedom vibration suppression to independently form a control loop, thereby achieving efficient suppression of five-degree-of-freedom vibration noise.
[0005] The technical solution of the present invention is as follows:
[0006] A five-degree-of-freedom active vibration isolation system is characterized by comprising a seismograph and a tiltmeter installed in the middle of the upper bearing platform of a passive vibration isolator. The seismograph is used to monitor the linear vibration of the upper bearing platform in the x, y, and z directions and outputs vibration voltage signals along the x-axis, y-axis, and z-axis. The tiltmeter is used to monitor the angular vibration of the upper bearing platform in the horizontal directions along the x and y axes and outputs angular vibration voltage signals along the x and y axes. The seismograph and tiltmeter are respectively connected to a main control computer. The main control computer is respectively connected to a first vertical z-axis force voice coil motor, a second vertical z-axis force voice coil motor, a third vertical z-axis force voice coil motor, a horizontal x-axis force voice coil motor, and a horizontal y-axis force voice coil motor installed along the four periphery of the upper bearing platform. The main control computer applies a control current to the voice coil motors through a voltage-controlled current source according to the voltage signal of the vibration to be suppressed, thereby driving the voice coil motors to generate a canceling vibration against the vibration to be suppressed, thus achieving five-degree-of-freedom active vibration isolation by independently suppressing the vibration of each degree of freedom.
[0007] The first vertical z-force voice coil motor, the second vertical z-force voice coil motor, and the third vertical z-force voice coil motor are distributed according to the three vertices of an equilateral triangle.
[0008] The first vertical z-axis force voice coil motor is located on the positive x-axis, the horizontal x-axis force voice coil motor is located on the negative x-axis, and the horizontal y-axis force voice coil motor is located on the negative y-axis.
[0009] Both the seismograph and the tiltmeter are connected to an analog voltage input and output board via their respective differential amplifier circuits. The analog voltage input and output board transmits the amplified vibration voltage signal to the main control computer.
[0010] The analog voltage input and output board converts the five-degree-of-freedom vibration analog voltage signal into a digital signal.
[0011] The main control computer simultaneously applies equal magnitude and direction current to the first, second, and third vertical z-force voice coil motors via a voltage-controlled current source, causing the three voice coil motors to generate the same vertical force, thereby suppressing vertical vibration.
[0012] The main control computer suppresses angular vibration around the y-axis by simultaneously applying equal and opposite currents to the second and third vertical z-force voice coil motors, while applying equal and opposite currents to the first vertical z-force voice coil motor.
[0013] The main control computer suppresses angular vibration around the x-axis by simultaneously applying equal and opposite currents to the second and third vertical z-force voice coil motors.
[0014] The main control computer applies a control current to the horizontal x-axis force voice coil motor through a voltage-controlled current source to suppress x-axis linear vibration, and / or the main control computer applies a control current to the horizontal y-axis force voice coil motor through a voltage-controlled current source to suppress y-axis vibration.
[0015] The technical effects of this invention are as follows: The five-degree-of-freedom active vibration isolation system of this invention, targeting passive vibration isolators, can construct five independent loops that apply vibration suppression through the combination of a seismograph, an inclinometer, a voice coil motor, and a main control computer, thereby achieving the suppression of linear vibration in three directions and the suppression of angular vibration in two directions on the horizontal plane, which is beneficial for providing vibration isolation for precision instruments.
[0016] The features of this invention are as follows:
[0017] (1) The present invention uses an inclinometer and a seismometer as vibration feedback sensors, combined with a designed voice coil motor mounting array, to achieve five-degree-of-freedom vibration suppression.
[0018] (2) In the vibration acquisition and force feedback, each degree of freedom can independently acquire vibration information and apply current to the voice coil motor. The vibration suppression control parameters of each degree of freedom can be designed independently to meet specific vibration suppression and system stability requirements. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the five-degree-of-freedom active vibration isolation system of the present invention.
[0020] Figure 2 This is a schematic diagram showing the relative positions of the voice coil motor with vertical z-axis force according to the present invention.
[0021] The reference numerals in the attached figures are explained as follows: 1-Passive vibration isolator; 2-Seismograph; 3-Inclinometer; 4-First vertical z-axis force voice coil motor; 5-Second vertical z-axis force voice coil motor; 6-Third vertical z-axis force voice coil motor; 7-Horizontal x-axis force voice coil motor; 8-Horizontal y-axis force voice coil motor; xyz-Three axes of the rectangular coordinate system (i.e., x-axis, y-axis, and z-axis). Detailed Implementation
[0022] The following is in conjunction with the attached diagram ( Figures 1-2 The invention will be described in the following sections and examples.
[0023] Figure 1 This is a schematic diagram of the five-degree-of-freedom active vibration isolation system of the present invention. Figure 2 This is a schematic diagram showing the relative positions of the voice coil motors subjected to vertical z-axis force according to the present invention. (Reference) Figures 1 to 2 As shown, a five-degree-of-freedom active vibration isolation system includes a seismograph 2 and a tiltmeter 3 installed in the middle of the upper bearing platform of the passive vibration isolator 1. The seismograph 2 is used to monitor the linear vibration of the upper bearing platform in the x, y, and z directions, and outputs vibration voltage signals along the x-axis, y-axis, and z-axis. The tiltmeter 3 is used to monitor the angular vibration of the upper bearing platform along the horizontal x-axis and y-axis, and outputs angular vibration voltage signals along the x-axis and y-axis. The seismograph 2 and tiltmeter 3 are respectively connected to a main control computer. The computer is connected to a first vertical z-axis force voice coil motor 4, a second vertical z-axis force voice coil motor 5, a third vertical z-axis force voice coil motor 6, a horizontal x-axis force voice coil motor 7, and a horizontal y-axis force voice coil motor 8, which are respectively arranged along the four periphery of the upper bearing platform. The main control computer applies control current to the voice coil motors through a voltage-controlled current source according to the voltage signal of the vibration to be suppressed, so as to drive the voice coil motors to generate a canceling vibration against the vibration to be suppressed, thereby achieving five-degree-of-freedom active vibration isolation by independently suppressing the vibration of each degree of freedom.
[0024] The first vertical z-force voice coil motor 4, the second vertical z-force voice coil motor 5, and the third vertical z-force voice coil motor 6 are distributed according to the three vertices of an equilateral triangle (see reference). Figure 2 (The center point to the adjacent lines of each voice coil motor form a 120-degree angle). The first vertical z-axis force voice coil motor 4 is located on the positive x-axis, the horizontal x-axis force voice coil motor 7 is located on the negative x-axis, and the horizontal y-axis force voice coil motor 8 is located on the negative y-axis.
[0025] Both the seismograph 2 and the tiltmeter 3 are connected to an analog voltage input and output board via their respective differential amplifier circuits. The analog voltage input and output board transmits the amplified vibration voltage signal to the main control computer. The analog voltage input and output board converts the five-degree-of-freedom vibration analog voltage signal into a digital signal.
[0026] The main control computer simultaneously applies equal magnitude and direction currents to the first vertical z-axis force voice coil motor 4, the second vertical z-axis force voice coil motor 5, and the third vertical z-axis force voice coil motor 6 via a voltage-controlled current source. This causes the three voice coil motors to generate the same vertical force, thereby suppressing vertical vibration. The main control computer also suppresses angular vibration around the y-axis by simultaneously applying equal magnitude and direction currents to the second vertical z-axis force voice coil motor 5 and the third vertical z-axis force voice coil motor 6, while applying equal magnitude and opposite direction currents to the first vertical z-axis force voice coil motor 4. Finally, the main control computer suppresses angular vibration around the x-axis by simultaneously applying equal magnitude and opposite direction currents to the second vertical z-axis force voice coil motor 5 and the third vertical z-axis force voice coil motor 6. The main control computer applies a control current to the horizontal x-axis force voice coil motor 7 through a voltage-controlled current source to suppress x-axis linear vibration, and / or the main control computer applies a control current to the horizontal y-axis force voice coil motor 8 through a voltage-controlled current source to suppress y-axis vibration.
[0027] This invention relates to a design method for a five-degree-of-freedom active vibration isolation system, comprising: a passive vibration isolator, a seismograph, a tiltmeter, a voltage-controlled current source, a differential amplifier circuit, five voice coil motors, and a main control computer. This invention constructs five independently applied vibration suppression loops, achieving suppression of linear vibrations in three directions and angular vibrations in two directions on the horizontal plane, providing vibration isolation for precision instruments.
[0028] like Figure 1 As shown, the five-degree-of-freedom active vibration isolation system of the present invention includes a passive vibration isolator (1), a seismograph (2), an inclinometer (3), a vertical z-axis force voice coil motor (a first vertical z-axis force voice coil motor 4, a second vertical z-axis force voice coil motor 5 and a third vertical z-axis force voice coil motor 6), a horizontal x-axis force voice coil motor (7), a horizontal y-axis force voice coil motor (8), a voltage-controlled current source, a differential amplifier circuit and a main control computer.
[0029] The passive vibration isolator (1) has its bottom support connected to the ground, and the upper bearing platform at the top holds the object to be isolated, a seismograph (2), and a tiltmeter (3). The seismograph monitors the linear vibrations of the upper bearing platform in the x, y, and z directions and outputs voltage signals corresponding to the three linear vibrations. The tiltmeter monitors the angular vibrations of the upper bearing platform in the horizontal directions along the x and y axes and outputs voltage signals corresponding to the two angular vibrations.
[0030] The seismograph (2) and inclinometer (3) are connected to the input of the differential amplifier circuit to amplify the vibration voltage signal according to the specified amplification factor. The output of the differential amplifier circuit is connected to the analog voltage input and output board of the main control computer to transmit the amplified vibration voltage signal to the main control computer.
[0031] The main control computer's analog voltage input acquisition board converts the five-degree-of-freedom vibration analog voltage signal input from the differential amplifier circuit into a digital signal. The active vibration isolation controller calculates and generates the corresponding vibration suppression control voltage signal based on the voltage signal of each degree of freedom vibration. The main control computer's analog voltage output board connects to the input terminal of the voltage-controlled current source, inputting the control voltage signal to the voltage-controlled current source.
[0032] The voltage-controlled current source connects the vertical force voice coil motor and the horizontal force voice coil motor, converting the vibration suppression control voltage signal from the main control computer into a current signal to drive the voice coil motor to counteract vibration.
[0033] In the vertical z-direction force voice coil motors (first vertical z-direction force voice coil motor 4, second vertical z-direction force voice coil motor 5 and third vertical z-direction force voice coil motor 6), the first vertical z-direction force voice coil motor (4) is installed at the midpoint of the frontmost baffle in the x-direction of the passive vibration isolator. The permanent magnet of the voice coil motor is fixed on the bearing platform of the passive vibration isolator, and the coil of the voice coil motor is fixed on the lower body of the passive vibration isolator.
[0034] like Figure 2 As shown, the first vertical z-force voice coil motor (4), the second vertical z-force voice coil motor (5), and the third vertical z-force voice coil motor (6) form an equilateral triangle and are fixed on the symmetrical sides of the y-axis at the same position on the x-axis of the passive vibration isolator. The main control computer applies equal magnitude and direction current to the three voice coil motors through a voltage-controlled current source, causing the three voice coil motors to generate the same vertical force, thereby suppressing vertical vibration. When equal magnitude and direction currents are applied to the second vertical z-force voice coil motor (5) and the second vertical z-force voice coil motor (6), while equal magnitude and opposite direction currents are applied to the first vertical z-force voice coil motor (4), angular vibration around the y-axis can be suppressed. When equal magnitude and opposite direction currents are applied to the second vertical z-force voice coil motor (5) and the third vertical z-force voice coil motor (6), angular vibration around the x-axis can be suppressed.
[0035] The horizontal x-axis force voice coil motor (7) and the horizontal y-axis force voice coil motor (8) are controlled by the main control computer through a voltage-controlled current source. The main control computer applies a control current to the horizontal x-axis force voice coil motor (7) to suppress the x-axis linear vibration. The main control computer applies a control current to the horizontal y-axis force voice coil motor (8) through a voltage-controlled current source to suppress the y-axis vibration.
[0036] In summary, the five-degree-of-freedom active vibration isolation system of the present invention enables each degree of freedom vibration suppression to independently form a control loop, thereby achieving efficient suppression of five-degree-of-freedom vibration noise.
[0037] Contents not described in detail in this specification are prior art known to those skilled in the art. It is hereby indicated that the above description is intended to help those skilled in the art understand this invention, but does not limit the scope of protection of this invention. Any equivalent substitutions, modifications, improvements, and / or simplifications of the above descriptions that do not depart from the essential content of this invention fall within the scope of protection of this invention.
Claims
1. A five-degree-of-freedom active vibration isolation system, characterized in that, The passive vibration isolator includes a seismograph and a tiltmeter installed in the middle of the upper bearing platform. The seismograph monitors the linear vibration of the upper bearing platform in the x, y, and z directions and outputs vibration voltage signals along the x, y, and z axes. The tiltmeter monitors the angular vibration of the upper bearing platform along the x and y axes in the horizontal directions and outputs angular vibration voltage signals along the x and y axes. The seismograph and tiltmeter are connected to a main control computer, which is connected to a first vertical z-axis force voice coil motor, a second vertical z-axis force voice coil motor, a third vertical z-axis force voice coil motor, a horizontal x-axis force voice coil motor, and a horizontal y-axis force voice coil motor installed around the periphery of the upper bearing platform. The main control computer applies a control current to the voice coil motors through a voltage-controlled current source based on the voltage signal of the vibration to be suppressed, thereby driving the voice coil motors to generate a canceling vibration against the vibration to be suppressed, thus achieving five-degree-of-freedom active vibration isolation by independently suppressing vibrations of each degree of freedom.
2. The five-degree-of-freedom active vibration isolation system according to claim 1, characterized in that, The first vertical z-force voice coil motor, the second vertical z-force voice coil motor, and the third vertical z-force voice coil motor are distributed according to the three vertices of an equilateral triangle.
3. The five-degree-of-freedom active vibration isolation system according to claim 2, characterized in that, The first vertical z-axis force voice coil motor is located on the positive x-axis, the horizontal x-axis force voice coil motor is located on the negative x-axis, and the horizontal y-axis force voice coil motor is located on the negative y-axis.
4. The five-degree-of-freedom active vibration isolation system according to claim 1, characterized in that, Both the seismograph and the tiltmeter are connected to an analog voltage input and output board via their respective differential amplifier circuits. The analog voltage input and output board transmits the amplified vibration voltage signal to the main control computer.
5. The five-degree-of-freedom active vibration isolation system according to claim 4, characterized in that, The analog voltage input and output board converts the five-degree-of-freedom vibration analog voltage signal into a digital signal.
6. The five-degree-of-freedom active vibration isolation system according to claim 1, characterized in that, The main control computer simultaneously applies equal magnitude and direction current to the first, second, and third vertical z-force voice coil motors via a voltage-controlled current source, causing the three voice coil motors to generate the same vertical force, thereby suppressing vertical vibration.
7. The five-degree-of-freedom active vibration isolation system according to claim 1, characterized in that, The main control computer suppresses angular vibration around the y-axis by simultaneously applying equal and opposite currents to the second and third vertical z-force voice coil motors, while applying equal and opposite currents to the first vertical z-force voice coil motor.
8. The five-degree-of-freedom active vibration isolation system according to claim 1, characterized in that, The main control computer suppresses angular vibration around the x-axis by simultaneously applying equal and opposite currents to the second and third vertical z-force voice coil motors.
9. The five-degree-of-freedom active vibration isolation system according to claim 1, characterized in that, The main control computer applies a control current to the horizontal x-axis force voice coil motor through a voltage-controlled current source to suppress x-axis linear vibration, and / or the main control computer applies a control current to the horizontal y-axis force voice coil motor through a voltage-controlled current source to suppress y-axis vibration.