Active vibration isolation method for cold atom gravimeter based on slow disturbance compensation

Abstract

The application provides a slow interference compensation-based active vibration isolation method for a cold atom gravimeter, relates to the technical field of active vibration isolation of a cold atom gravimeter, and comprises the following steps: establishing an active vibration isolation model for the cold atom gravimeter; designing a slow interference compensation law; designing a Lyapunov stable function; and designing a compensation proportional integral differential control law, so that the problem that current control methods do not consider random vibration caused by ground vibration and natural environment is solved, the problem that the control methods cannot adapt to vibration environment change requirements is solved, the slow interference compensation-based active vibration isolation method for the cold atom gravimeter makes the vibration speed and vibration displacement of the active vibration isolation system of the cold atom gravimeter converge rapidly, and the control precision of the active vibration isolation system of the cold atom gravimeter is improved.

Description

Technical Field

[0001] This invention relates to the field of active vibration isolation technology for cold atom gravimeters, and in particular to an active vibration isolation method for cold atom gravimeters based on slow disturbance compensation. Background Technology

[0002] Cold atom gravimeters are a novel type of quantum sensor that has developed rapidly over the past two decades. They utilize laser cooling, atomic interferometry, and other technologies to achieve high-precision, high-sensitivity measurements of gravitational acceleration. Currently, the measurement accuracy of cold atom gravimeters has reached the microgal level, making them suitable for precision engineering measurements in areas such as mineral resource exploration, geological structure research, oil and gas prospecting, determination of spectroscopic constant brightness in scientific fields, and inter-matter gravitational forces.

[0003] In practical measurements, the accuracy of atomic gravity measurements is affected by ground vibration noise, Raman phase noise, and detection noise, among which vibration noise is the most significant factor affecting atomic gravimeters. Currently, the natural frequency of commercially available passive vibration isolation platforms can be adjusted down to as low as 0.5 Hz, which can be used to isolate the influence of ground vibrations above 10 Hz on atomic gravimeters. However, atomic gravimeters are more sensitive to vibrations in the 0.1-10 Hz range, so a simple passive vibration isolation platform cannot meet the vibration isolation requirements of atomic gravimeters. Although the natural frequency of the entire passive vibration isolation platform can be adjusted, if the natural frequency is adjusted too low, the entire system will exhibit nonlinear effects. Ground vibrations near the passive isolation natural frequency will not only not be suppressed, but will actually increase on top of the original vibration. Therefore, an active vibration isolation system needs to be introduced to suppress vibrations in this frequency band.

[0004] However, active vibration isolation systems are affected by a large number of uncertain factors, and current control methods do not take into account ground vibration and random vibrations caused by the natural environment, so they cannot adapt to the requirements of changing vibration environments. Summary of the Invention

[0005] This invention discloses an active vibration isolation method for cold atom gravimeters based on slow disturbance compensation. This method solves the problem that current control methods do not consider ground vibration and random vibration caused by the natural environment, resulting in an inability to adapt to changes in the vibration environment. The active vibration isolation method for cold atom gravimeters based on slow disturbance compensation enables the vibration velocity and vibration displacement of the active vibration isolation system of the cold atom gravimeter to converge rapidly, thereby improving the control accuracy of the active vibration isolation system of the cold atom gravimeter.

[0006] The technical solution of this invention is implemented as follows:

[0007] This invention discloses an active vibration isolation method for cold atom gravimeters based on slow disturbance compensation, comprising the following steps:

[0008] Establish an active vibration isolation model for a cold atom gravimeter;

[0009] Design a slow disturbance compensation law;

[0010] Design a Lyapunov stable function;

[0011] Design a proportional-integral-derivative control law with compensation.

[0012] Furthermore, the steps for establishing an active vibration isolation model for a cold atom gravimeter include:

[0013]

[0014] Where ξ0 is the system's inherent damping coefficient, ω0 is the system's natural frequency, F is the force generated by the voice coil motor, and x is the vibration displacement of the Raman mirror. Let be the vibration velocity of the Raman mirror. Let y be the vibration acceleration of the Raman mirror, and y be the ground vibration displacement. Let m be the ground vibration velocity, m be the mass of the Raman mirror, u be the controller input, and K be the ground vibration velocity. VC Y is the gain coefficient of the voice coil motor. VC This is the voltage-to-current gain coefficient;

[0015] make,

[0016] Then equation (1) is:

[0017]

[0018] Furthermore, the steps for designing the slow disturbance compensation law include:

[0019] The slow disturbance compensation law is designed as follows:

[0020]

[0021] in, To The estimate, for The first derivative, For the estimation of d, for The first derivative of , k1 is the gain coefficient and k1 > 0, k2 is the gain coefficient and k2 > 0.

[0022] Furthermore, the steps for designing the Lyapunov stable function include:

[0023] Design the Lyapunov stability function V as follows:

[0024]

[0025] in

[0026] Then it exists:

[0027]

[0028] in, Let V be the first derivative. for The first derivative, for The first derivative, The first derivative of d;

[0029] Assume the interference d is a slow time-varying signal. When k1 is very small, then when a larger value is taken, we have:

[0030]

[0031] Substituting equations (3), (4), and (7) into equation (6), we get:

[0032]

[0033] Furthermore, the steps for designing a compensated proportional-integral-derivative control law include:

[0034] The control law u after compensation is:

[0035]

[0036] Where, e = x d -x, Let e ​​be the first derivative. Let x be the integral of e with respect to time t. d Here, b is the ideal setpoint for vibration, b is the gain coefficient and b > 0, k3 is the gain coefficient and k3 > 0, k4 is the gain coefficient and k4 > 0, and k5 is the gain coefficient and k5 > 0.

[0037] Beneficial technical effects:

[0038] This invention provides an active vibration isolation method for cold atom gravimeters based on slow disturbance compensation, comprising the following steps: establishing an active vibration isolation model for the cold atom gravimeter; designing a slow disturbance compensation law; designing a Lyapunov stability function; and designing a compensated proportional-integral-derivative control law. This solves the problem that current control methods do not consider ground vibration and random vibrations caused by the natural environment, resulting in an inability to adapt to changes in the vibration environment. The active vibration isolation method for cold atom gravimeters based on slow disturbance compensation enables the vibration velocity and vibration displacement of the active vibration isolation system of the cold atom gravimeter to converge rapidly, thereby improving the control accuracy of the active vibration isolation system of the cold atom gravimeter. Attached Figure Description

[0039] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0040] Figure 1 This is a flowchart illustrating the steps of the active vibration isolation method for a cold atom gravimeter based on slow interference compensation as described in this invention.

[0041] Figure 2 When the ground vibration frequency is 0.1Hz and the external environmental vibration interference displacement amplitude is 1mm, the active vibration isolation method of the cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration displacement suppression effect of no vibration isolation control.

[0042] Figure 3 When the ground vibration frequency is 0.1Hz and the external environmental vibration interference velocity amplitude is 62.8mm / s, the active vibration isolation method of cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration velocity suppression effect of no vibration isolation control.

[0043] Figure 4 When the ground vibration frequency is 0.2Hz and the external environmental vibration interference displacement amplitude is 1mm, the active vibration isolation method of cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration displacement suppression effect of no vibration isolation control.

[0044] Figure 5 When the ground vibration frequency is 0.2Hz and the external environmental vibration interference velocity amplitude is 31.4mm / s, the active vibration isolation method of cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration velocity suppression effect of vibration isolation control without implementation.

[0045] Figure 6 When the ground vibration frequency is 0.5Hz and the external environmental vibration interference displacement amplitude is 1mm, the active vibration isolation method of cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration displacement suppression effect of no vibration isolation control.

[0046] Figure 7 When the ground vibration frequency is 0.5Hz and the external environmental vibration interference signal has a vibration velocity amplitude of 12.56mm / s, the active vibration isolation method of cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration velocity suppression effect of no vibration isolation control.

[0047] Figure 8When the ground vibration frequency is 1Hz and the external environmental vibration interference displacement amplitude is 1mm, the vibration displacement suppression effect of the cold atom gravimeter active vibration isolation method based on slow interference compensation described in this invention is compared with that of vibration displacement suppression without vibration isolation control.

[0048] Figure 9 When the ground vibration frequency is 1Hz and the external environmental vibration interference amplitude is 6.28mm / s, the active vibration isolation method of cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration velocity suppression effect of vibration isolation control without implementation.

[0049] Figure 10 When the ground vibration frequency is 2Hz and the external environmental vibration interference displacement amplitude is 1mm, the active vibration isolation method of the cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration displacement suppression effect of no vibration isolation control.

[0050] Figure 11 When the ground vibration frequency is 2Hz and the external environmental vibration interference amplitude is 3.14mm / s, the active vibration isolation method of cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration velocity suppression effect of vibration isolation control without implementation. Figure 12 The external environmental vibration interference is a random interference signal that is white noise;

[0051] Figure 12 When the ground vibration frequency is 5Hz and the external environmental vibration interference displacement amplitude is 1mm, the active vibration isolation method of cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration displacement suppression effect of no vibration isolation control.

[0052] Figure 13 When the ground vibration frequency is 5Hz and the external environmental vibration interference signal has a vibration velocity amplitude of 3.14mm / s, the active vibration isolation method of cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration velocity suppression effect of vibration isolation control without implementation.

[0053] Figure 14 When the ground vibration frequency is 10Hz and the external environmental vibration interference displacement amplitude is 1mm, the active vibration isolation method of cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration displacement suppression effect of no vibration isolation control.

[0054] Figure 15When the ground vibration frequency is 10Hz and the external environmental vibration interference signal has a vibration velocity amplitude of 0.628mm / s, the active vibration isolation method of cold atom gravimeter based on slow interference compensation described in this invention is compared with the vibration velocity suppression effect of vibration isolation control without implementation.

[0055] Figure 16 The method for active vibration isolation of a cold atom gravimeter based on slow interference compensation, as described in this invention, is compared with the vibration displacement suppression effect of a method without vibration isolation control, where the external environmental vibration interference is a random interference signal of white noise. Detailed Implementation

[0056] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0057] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0058] This invention discloses an active vibration isolation method for cold atom gravimeters based on slow disturbance compensation. See [link to relevant documentation]. Figure 1 Specifically, it includes the following steps:

[0059] S1: Establish an active vibration isolation model for a cold atom gravimeter;

[0060] Specifically, the steps for establishing an active vibration isolation model for a cold atom gravimeter include:

[0061]

[0062] Where ξ0 is the system's inherent damping coefficient, ω0 is the system's natural frequency, F is the force generated by the voice coil motor, and x is the vibration displacement of the Raman mirror. Let be the vibration velocity of the Raman mirror. Let y be the vibration acceleration of the Raman mirror, and y be the ground vibration displacement. Let m be the ground vibration velocity, m be the mass of the Raman mirror, u be the controller input, and K be the ground vibration velocity. VC Y is the gain coefficient of the voice coil motor. VC This is the voltage-to-current gain coefficient;

[0063] make,

[0064] Then equation (1) is:

[0065]

[0066] S2: Design a slow disturbance compensation law;

[0067] Specifically, the steps for designing a slow disturbance compensation law include:

[0068] The slow disturbance compensation law is designed as follows:

[0069]

[0070] in, To The estimate, for The first derivative, For the estimation of d, for The first derivative of , k1 is the gain coefficient and k1 > 0, k2 is the gain coefficient and k2 > 0.

[0071] S3: Design a Lyapunov stable function;

[0072] Specifically, the steps for designing a Lyapunov stable function include:

[0073] Design the Lyapunov stability function V as follows:

[0074]

[0075] in

[0076] Then it exists:

[0077]

[0078] in, Let V be the first derivative. for The first derivative, for The first derivative, The first derivative of d;

[0079] Assume the interference d is a slow time-varying signal. When k1 is very small, then when a larger value is taken, we have:

[0080]

[0081] Substituting equations (3), (4), and (7) into equation (6), we get:

[0082]

[0083] S4: Design a proportional-integral-derivative control law for compensation.

[0084] Specifically, the steps for designing a compensated proportional-integral-derivative control law include:

[0085] This invention achieves compensation by effectively observing the disturbance d; therefore, the control law after compensation is as follows:

[0086]

[0087] Where, e = x d -x, Let e ​​be the first derivative. Let x be the integral of e with respect to time t. d Here, b is the ideal setpoint for vibration, b is the gain coefficient and b > 0, k3 is the gain coefficient and k3 > 0, k4 is the gain coefficient and k4 > 0, and k5 is the gain coefficient and k5 > 0.

[0088] As an embodiment of the present invention, the experimental simulation parameters for an active vibration isolation method for a cold atom gravimeter based on slow disturbance compensation disclosed in the present invention are set as follows:

[0089] Set the system damping coefficient ξ0 = 0.1 N·s·m -1 The system's natural frequency ω0 = 4.396 rad, and the voice coil motor current gain coefficient K VC =0.1V·A -1 Voltage-to-current gain coefficient Y VC =7.6 N·A -1 The mass of the Raman mirror is m = 10 kg; the compensation gain parameter k1 = 50, the gain parameter k2 = 2000, the compensation proportional-integral-derivative control law gain parameter k3 = 100, the gain parameter k4 = 10, and the gain parameter k5 = 0 are for the active vibration isolation method of the cold atom gravimeter based on slow disturbance compensation proportional-integral-derivative control.

[0090] This invention discloses an active vibration isolation method for cold atom gravimeters based on slow disturbance compensation, which enables the vibration velocity and displacement of the active vibration isolation system of the cold atom gravimeter to converge rapidly, greatly improving the control accuracy of the active vibration isolation system of the cold atom gravimeter. Figures 2-16 The comparison results of the active vibration isolation method for cold atom gravimeters based on proportional-integral-derivative control with slow disturbance compensation disclosed in the embodiments of the present invention and the method without vibration isolation control are shown. The vibration displacement of the cold atom gravimeter after active vibration isolation control based on slow disturbance compensation is much smaller than that without vibration isolation control; the vibration velocity of the cold atom gravimeter after active vibration isolation control based on slow disturbance compensation is much smaller than that without vibration isolation control. It can be seen that the advantages of the active vibration isolation method for cold atom gravimeters based on slow disturbance compensation disclosed in the present invention are obvious.

[0091] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0092] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An active vibration isolation method for cold atom gravimeters based on slow disturbance compensation, characterized in that, Includes the following steps: Establish an active vibration isolation model for a cold atom gravimeter; The steps for establishing an active vibration isolation model for a cold atom gravimeter include: （1） in, The system's inherent damping coefficient, The natural frequency of the system. This represents the vibrational displacement of the Raman mirror. Let be the vibration velocity of the Raman mirror. The vibration acceleration of the Raman mirror. This represents ground vibration displacement. Ground vibration velocity, For the quality of the Raman mirror, For controller input, This represents the gain coefficient of the voice coil motor. This is the voltage-to-current gain coefficient; make, , Then equation (1) is: （2）； Design a slow disturbance compensation law; The steps involved in designing a slow disturbance compensation law include: The slow disturbance compensation law is designed as follows: （3） （4） in, To The estimate, for The first derivative, To The estimate, for The first derivative, The gain coefficient and , The gain coefficient and ; Design a Lyapunov stable function; The steps involved in designing a Lyapunov stable function include: Design a Lyapunov stability function. for: （5） in, ; Then it exists: （6） in, for The first derivative, for The first derivative, for The first derivative, for The first derivative; Assuming interference It is a slow time-varying signal. Very small, when taken For larger values, then: （7） Substituting equations (3), (4), and (7) into equation (6), we get: （8）； Design a proportional-integral-derivative control law with compensation; The steps involved in designing a compensated proportional-integral-derivative control law include: Control Law with Compensation for: （9） （10） in, , for The first derivative, for Regarding time The points, The ideal setpoint for vibration, The gain coefficient and , The gain coefficient and , The gain coefficient and , The gain coefficient and .

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