An electrostatic accelerometer and its zero adjustment method

Abstract

The present application belongs to the field of electrostatic accelerometers, and specifically discloses an electrostatic accelerometer and a zero position adjustment method thereof, the method comprising: when the external acceleration acting on the capacitor plate is an acceleration in a first direction, adjusting the control zero position of the test mass to a first position range; when the external acceleration acting on the capacitor plate is an acceleration in a second direction, adjusting the control zero position of the test mass to a second position range; wherein, the first position range is the position of the test mass when the distance of the test mass relative to the first capacitor plate is less than the distance of the test mass relative to the second capacitor plate, and the second position range is the position of the test mass when the distance of the test mass relative to the first capacitor plate is greater than the distance of the test mass relative to the second capacitor plate; the position of the test mass is the distance between the center of the test mass and the axis of symmetry of the two capacitor plates. Through this application, the present application effectively improves the range of the electrostatic accelerometer on the basis of the traditional electrostatic accelerometer.

Description

Technical Field

[0001] The present application belongs to the field of electrostatic accelerometers, and more specifically, relates to an electrostatic accelerometer and a zero adjustment method thereof. Background Art

[0002] High-precision electrostatic accelerometers, as indispensable payloads in key missions such as satellite gravity measurement, have achieved remarkable and extensive application results in international space exploration. In space science research, the continuous improvement of the accuracy of inertial sensors has become a key issue that needs to be addressed urgently. The core operating mechanism of the electrostatic accelerometer relies on the proof mass in its sensitive probe. As the benchmark for inertial measurement, the proof mass plays a vital role. When the spacecraft is disturbed by an external non-conservative force, the proof mass will deviate from its equilibrium position, thereby causing a change in the capacitance value between it and the corresponding plate. The capacitance difference is accurately measured by the capacitive displacement sensing circuit and converted into the displacement information of the proof mass relative to the equilibrium point, that is, the residual signal.

[0003] The residual signal is then processed by a controller and converted into a corresponding feedback voltage, which acts on the electrostatic actuator to generate the appropriate electrostatic force to accurately pull the test mass back to its equilibrium position. During this process, the acceleration generated by the electrostatic actuator matches the acceleration of the spacecraft. This equilibrium relationship can be described by the following expression:

[0004]

[0005] Among them, a in is the external input acceleration; a n,dir is the direct disturbance acceleration of the test mass; a f is the feedback acceleration generated on the test mass by the electrostatic force; x is the relative position of the test mass and the capacitor plate; is the electrostatic negative stiffness represented by angular frequency; s represents the first differential link.

[0006] The traditional electrostatic accelerometer controls the test mass to zero position (x = 0 [m]) and feeds back the acceleration a f As the external input acceleration a in The approximate measurement result of a f It can be calculated from the feedback voltage data. The calculation process is as follows:

[0007] a f =H a ·V f

[0008] Among them, H a is the feedback actuator transfer function, V f is the feedback voltage.

[0009] As the core device in the inertial system, the electrostatic accelerometer has high requirements for its controllability and range. Traditional solutions generally use electrostatic actuators to control the test mass to zero (x = 0 [m]). When there is a quasi-static input acceleration signal, the electrostatic actuator needs to continuously output the feedback voltage V f Generate feedback acceleration to offset input disturbance (a f ≈a in ), and when the input acceleration exceeds the zero range of the electrostatic actuator, it will cause the inspection quality to be out of control and hit the plate frame. Summary of the Invention

[0010] In view of the defects of the prior art, the purpose of this application is to provide an electrostatic accelerometer and a zero adjustment method thereof, aiming to solve the problem of limited range caused by the fixed zero control of the existing electrostatic accelerometer.

[0011] To achieve the above objectives, in a first aspect, the present application provides a zero adjustment method for an electrostatic accelerometer, the electrostatic accelerometer comprising: a sensitive probe; the sensitive probe comprising: a proof mass, a first capacitor plate, and a second capacitor plate, the proof mass being disposed between the two capacitor plates, the first capacitor plate being located in a first direction of the proof mass, and the second capacitor plate being located in a second direction of the proof mass; the method comprising:

[0012] When the external acceleration acting on the capacitor plate is an acceleration in a first direction, adjusting the control zero position of the proof mass to a first position range;

[0013] When the external acceleration acting on the capacitor plate is an acceleration in a second direction, adjusting the control zero position of the proof mass to a second position range;

[0014] Among them, the first position range is the position of the inspection mass when the distance between the inspection mass and the first capacitor plate is smaller than the distance between the inspection mass and the second capacitor plate, and the second position range is the position of the inspection mass when the distance between the inspection mass and the first capacitor plate is larger than the distance between the inspection mass and the second capacitor plate; the position of the inspection mass is the distance between the center of the inspection mass and the axis of symmetry of the two capacitor plates.

[0015] In some embodiments, the adjustment range of the control zero position is: d0 is the distance between the outer edge of the test mass and the two capacitor plates when the test mass is arranged symmetrically relative to the two capacitor plates.

[0016] In some embodiments, let the control zero position be x cmd , the range a of the electrostatic accelerometer under the control zero position mea for:

[0017]

[0018] Among them, V f is the feedback voltage used to drive the test mass to reach the control zero position x cmd ;H a To provide feedback voltage V f The transfer function of the feedback actuator; ω e is the angular frequency corresponding to the electrostatic stiffness of the electrostatic accelerometer.

[0019] In some embodiments, when the control zero position x cmd In the first position range, x cmd Greater than 0; when the control zero position x cmd In the second position range, x cmd Less than 0.

[0020] In a second aspect, the present application provides an electrostatic accelerometer, comprising: a sensitive probe and a control zero adjustment module;

[0021] The sensitive probe comprises: a test mass, a first capacitor plate and a second capacitor plate, wherein the test mass is arranged between the two capacitor plates, the first capacitor plate is located in a first direction of the test mass, and the second capacitor plate is located in a second direction of the test mass;

[0022] The control zero position adjustment module is configured to adjust the control zero position of the proof mass to a first position range when the external acceleration acting on the capacitor plate is an acceleration in a first direction;

[0023] The control zero position adjustment module is further configured to adjust the control zero position of the proof mass to a second position range when the external acceleration acting on the capacitor plate is an acceleration in a second direction;

[0024] Among them, the first position range is the position of the inspection mass when the distance between the inspection mass and the first capacitor plate is smaller than the distance between the inspection mass and the second capacitor plate, and the second position range is the position of the inspection mass when the distance between the inspection mass and the first capacitor plate is larger than the distance between the inspection mass and the second capacitor plate; the position of the inspection mass is the distance between the center of the inspection mass and the axis of symmetry of the two capacitor plates.

[0025] In some embodiments, the control zero position adjustment module adjusts the control zero position within a range of: d0 is the distance between the outer edge of the test mass and the two capacitor plates when the test mass is arranged symmetrically relative to the two capacitor plates.

[0026] In some embodiments, let the control zero position be x cmd , the range a of the electrostatic accelerometer under the control zero position mea for:

[0027]

[0028] Among them, V f is the feedback voltage used to drive the test mass to reach the control zero position x cmd ;H a To provide feedback voltage V f The transfer function of the feedback actuator; ω e is the angular frequency corresponding to the electrostatic stiffness of the electrostatic accelerometer.

[0029] In some embodiments, when the control zero position x cmd In the first position range, x cmd Greater than 0; when the control zero position x cmd In the second position range, x cmd Less than 00.

[0030] In a third aspect, the present application provides an electronic device, comprising:

[0031] at least one memory for storing a computer program;

[0032] At least one processor is used to execute the program stored in the memory. When the program stored in the memory is executed, the processor is used to execute the method described in the first aspect or any embodiments of the first aspect.

[0033] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the existing technologies:

[0034] The present application provides an electrostatic accelerometer with adjustable control zero position. The traditional electrostatic accelerometer measurement solution has a fixed control zero position (x cmd =0m), when there is a quasi-static input acceleration signal, the electrostatic actuator needs to always output the feedback voltage V f Generate feedback acceleration to offset input disturbance (a in ≈a f ). Furthermore, when the input acceleration exceeds the zero range of the electrostatic actuator, it can cause the test mass to lose control and collide with the plate frame. This fixed zero position limits the controllability and effective range of the electrostatic accelerometer. This application adds a controlled zero position adjustment to the traditional electrostatic accelerometer, effectively extending the range of the electrostatic accelerometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of an electrostatic accelerometer with adjustable zero position control provided in an embodiment of the present application;

[0036] Figure 2 Schematic diagram of single-degree-of-freedom electrostatic control of an electrostatic accelerometer provided in an embodiment of the present application;

[0037] Figure 3 Schematic diagram of the range of an electrostatic actuator with the inspection mass at different positions provided in an embodiment of the present application;

[0038] Figure 4 This is a schematic diagram of the time-domain displacement simulation results of the new solution provided in the embodiment of the present application;

[0039] Figure 5 This is a schematic diagram of the time-domain acceleration signal simulation results of the new solution provided in the embodiment of the present application;

[0040] In all drawings, the same reference numerals are used to represent the same elements or structures, where: 1 is the inspection mass; 2 is the capacitor plate; 3 is the capacitor displacement sensing circuit; 4 is the controller; 5 is the feedback actuator; 6 is the signal driver; and 7 is the control zero adjustment processor. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0042] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0043] In response to the shortcomings of the prior art, the present application aims to provide an electrostatic accelerometer with an adjustable control zero position. This aims to address the actuator range limitations caused by the fixed control zero position of existing electrostatic accelerometers, realize the function of adjusting the control zero position of the electrostatic accelerometer, and improve the controllability of the electrostatic accelerometer. The present application provides an electrostatic accelerometer with an adjustable control zero position. Based on the traditional electrostatic accelerometer, a control zero position adjustment processor is added. The control zero position is adjusted according to the feedback voltage, effectively improving the range of the electrostatic accelerometer.

[0044] like Figure 1 As shown, an electrostatic accelerometer with adjustable control zero position provided in an embodiment of the present application includes: a test mass 1, a capacitor plate 2, a capacitive displacement sensing circuit 3, a controller 4, a feedback actuator 5, a signal driver 6, a control zero position adjustment processor 7 and an analog-to-digital converter ADC; the sensitive probe includes the test mass 1 and the capacitor plate 2;

[0045] Two capacitor plates 2 are provided in parallel on each side of the test mass 1; the input end of the capacitance displacement sensing circuit 3 is connected to the capacitor plates 2, and the output end thereof is connected to the controller 4; the output end of the controller 4 is connected to the feedback actuator 5; the output end of the feedback actuator 5 is connected to the capacitor plates 2; and the output end of the signal driver 6 is connected to the test mass 1;

[0046] The sensitive probe includes a capacitor plate and a test mass; the test mass is used to generate displacement relative to the equilibrium position under the action of external interference force; the capacitive displacement sensing circuit is used to test the position of the test mass in the capacitor plate and convert the displacement signal into a voltage signal; the controller is used to convert the displacement signal into a feedback voltage and transmit it to the feedback actuator, wherein the feedback voltage is used to control the test mass; the feedback actuator is used to apply the feedback voltage obtained by the controller to the capacitor plate to generate electrostatic force; the signal driver is used to provide a carrier signal and a DC bias voltage to the test mass, wherein the carrier is used to modulate the capacitance difference signal generated by the displacement of the test mass to a preset frequency, and the bias voltage is used to linearize the feedback actuator; the control zero position adjustment processor is used to calculate the control zero position instruction required to offset the external input acceleration signal based on the feedback voltage signal; the analog-to-digital converter ADC is used to convert the feedback voltage signal and the residual voltage signal from analog signals to digital signals.

[0047] Traditional electrostatic accelerometers drive the test mass to zero position by applying feedback voltage, and use the feedback voltage data to calculate the feedback acceleration, which is used as the measurement result of the external input acceleration. In order to improve the measurement and control range of the electrostatic accelerometer, this application adds a control zero position adjustment processor on the basis of the traditional electrostatic accelerometer to change the control zero position of the electrostatic accelerometer, thereby improving the measurement range of the electrostatic accelerometer.

[0048] like Figure 2 As shown, the sensitive probe of the electrostatic accelerometer includes: a test mass, a first capacitor plate and a second capacitor plate, wherein the test mass is arranged between the two capacitor plates. Figure 2 Medium V b is the DC bias voltage applied to the test mass; taking the electrostatic accelerometer measuring the acceleration in the z-axis direction as an example, Figure 2 As shown, the first capacitor plate is located in a first direction of the proof mass (e.g. Figure 2 ), the second capacitor plate is located in a second direction of the proof mass (e.g. Figure 2 The zero adjustment method specifically includes:

[0049] When the external acceleration acting on the capacitor plate is the first direction acceleration (in Figure 2 , adjusting the control zero position of the proof mass to a first position range;

[0050] When the external acceleration acting on the capacitor plate is the second direction acceleration (in Figure 2 (corresponding to downward acceleration), adjusting the control zero position of the proof mass to a second position range;

[0051] Among them, the first position range is the position of the inspection mass when the distance between the inspection mass and the first capacitor plate is less than the distance between the inspection mass and the second capacitor plate, and the second position range is the position of the inspection mass when the distance between the inspection mass and the first capacitor plate is greater than the distance between the inspection mass and the second capacitor plate; the position of the inspection mass is the distance between the center of the inspection mass and the symmetry axis of the two capacitor plates, that is, Figure 2 The x shown in .

[0052] Specifically, the function of the control zero adjustment processor is to adjust the input acceleration a in Size adjustment control zero position x cmd The input acceleration is the acceleration acting on the capacitor plates. The greater the input acceleration, the larger the control zero position will be, maximizing the range of the electrostatic accelerometer. To avoid edge effects (nonlinear control effects) caused by the test mass being too close to the plate frame, the control zero position adjustment range is limited as follows:

[0053]

[0054] The feedback controller K sus1 The function is to apply feedback voltage V f , drives the test mass to the new zero position x cmd d0 is the distance between the outer edge of the test mass and the two capacitor plates when the test mass is symmetrically arranged relative to the two capacitor plates, as shown in Figure 2 shown.

[0055] The measurement range of the electrostatic accelerometer with adjustable zero position is as follows:

[0056]

[0057] The control zero position x of the traditional electrostatic accelerometer cmd =0, the measuring range is H a V f .

[0058] This solution improves the measurement accuracy by adjusting the control zero position.

[0059] Control zero position adjustable electrostatic actuator range Figure 3 As shown, the blue curve is V f =-10[V] The electrostatic actuator range with the test mass in different positions. The yellow curve is V f =10[V] The range of the electrostatic actuator with the test mass in different positions. The red curve is V f =0[V] The range of the electrostatic actuator when the test mass is at different positions. It can be seen that when the test mass is at 0m, the range of the electrostatic actuator is ±1.03×10-4 m / s 2 ; Inspection quality is When the electrostatic actuator has a measuring range of 0 to 4.59×10 -4 m / s 2 ; When the inspection quality is The range of the electrostatic actuator is -4.59×10 -4 ~0m / s 2 The control zero adjustment processor integrates the feedback voltage value to determine the control zero command. The feedback voltage value reflects the magnitude and direction of the input acceleration. With the first direction as the positive direction, the corresponding first position range is the positive position. When the input acceleration is positive or negative, the control zero adjustment adjuster adjusts the proof mass to the positive position to increase the electrostatic accelerometer range in the positive direction. The same principle applies in the opposite direction (i.e., with the second direction as the negative direction, the corresponding second position range is the negative position). In short, the total range of the electrostatic accelerometer in both positive and negative directions is achieved by adjusting the proof mass displacement in both positive and negative directions.

[0060] In summary, when the control zero position is When adjusting between the two, since electrostatic accelerometers are usually used in scenarios where the external acceleration changes slowly, such as space, there will be no large sudden changes in external acceleration (such as a sudden increase or a sudden change in direction, etc.); it can be seen that the solution provided in this application can increase the dynamic range of the inspection quality by 2 times and the steady-state range by 4 times.

[0061] In order to test the ability of the new solution to increase the measurement range of the electrostatic actuator, the following Figure 4 and Figure 5 The simulation verification is shown. Figure 4 The blue solid line x is the actual displacement curve of the inspection mass, and the red dotted line x is the time domain displacement simulation result of the new solution provided in the embodiment of the present application. cmd is the given displacement instruction, the yellow solid line x err is the difference between the actual displacement of the test mass and the displacement command, the black dotted line Represents half the distance between the plates. Figure 5 This is the time domain acceleration signal simulation result of the new solution provided in the embodiment of the present application. The yellow solid line a mea * Is the measured acceleration, the purple dotted line a in is the input acceleration signal, and the black solid line represents the electrostatic actuator range when the control zero position is zero.

[0062] Combine Figure 4 and Figure 5 It can be seen that given ±4×10 -4 m / s 2The sinusoidal input acceleration signal is shown in the figure. As can be seen from the figure, with the introduction of input acceleration, the zero position regulator is controlled to continuously adjust the zero position to change the relative displacement of the test mass, so that the electrostatic accelerometer can generate a larger acceleration to offset the input acceleration and maintain a stable state at all times. The simulation results verify the function of this scheme to improve the range of the electrostatic actuator.

[0063] In summary, in order to realize the function of adjusting the zero position of the electrostatic accelerometer, the present application adds a control zero position adjustment on the basis of the traditional electrostatic accelerometer, thereby effectively improving the range of the electrostatic accelerometer.

[0064] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0065] In addition, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0066] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the two are connected to each other and the relative position relationship after the connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after the connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after the connection. The directional terms mentioned in the embodiments of the present application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0067] In addition, in the embodiments of the present application, the mathematical concepts mentioned include symmetry, equality, parallelism, and perpendicularity. These limitations are all for the current state of the art, rather than being absolutely strict definitions in a mathematical sense. A small amount of deviation is allowed, and it is possible to be approximately symmetric, approximately equal, approximately parallel, or approximately perpendicular. For example, A and B are parallel, which means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. A and B are perpendicular, which means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0068] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A zero adjustment method for an electrostatic accelerometer, the electrostatic accelerometer comprising: Sensitive probe; The sensitive probe comprises: a proof mass, a first capacitor plate, and a second capacitor plate, wherein the proof mass is disposed between the two capacitor plates, the first capacitor plate being located in a first direction of the proof mass, and the second capacitor plate being located in a second direction of the proof mass; and is characterized in that: When the external acceleration acting on the capacitor plate is an acceleration in a first direction, adjusting the control zero position of the proof mass to a first position range; When the external acceleration acting on the capacitor plate is an acceleration in a second direction, adjusting the control zero position of the proof mass to a second position range; Among them, the first position range is the position of the inspection mass when the distance between the inspection mass and the first capacitor plate is smaller than the distance between the inspection mass and the second capacitor plate, and the second position range is the position of the inspection mass when the distance between the inspection mass and the first capacitor plate is larger than the distance between the inspection mass and the second capacitor plate; the position of the inspection mass is the distance between the center of the inspection mass and the axis of symmetry of the two capacitor plates.

2. The method according to claim 1, characterized in that The adjustment range of the control zero position is: d0 is the distance between the outer edge of the test mass and the two capacitor plates when the test mass is arranged symmetrically relative to the two capacitor plates.

3. The method according to claim 1 or 2, characterized in that Let the control zero position be x cmd , the range a of the electrostatic accelerometer under the control zero position mea for: Among them, V f is the feedback voltage used to drive the test mass to reach the control zero position x cmd ;H a To provide feedback voltage V f The transfer function of the feedback actuator; ω e is the angular frequency corresponding to the electrostatic stiffness of the electrostatic accelerometer.

4. The method according to claim 3, characterized in that When the control zero position x cmd In the first position range, x cmd Greater than 0; when the control zero position x cmd In the second position range, x cmd Less than 0.

5. An electrostatic accelerometer, characterized in that: include: Sensitive probe and control zero adjustment module; The sensitive probe comprises: a test mass, a first capacitor plate and a second capacitor plate, wherein the test mass is arranged between the two capacitor plates, the first capacitor plate is located in a first direction of the test mass, and the second capacitor plate is located in a second direction of the test mass; The control zero position adjustment module is configured to adjust the control zero position of the proof mass to a first position range when the external acceleration acting on the capacitor plate is an acceleration in a first direction; The control zero position adjustment module is further configured to adjust the control zero position of the proof mass to a second position range when the external acceleration acting on the capacitor plate is an acceleration in a second direction; Among them, the first position range is the position of the inspection mass when the distance between the inspection mass and the first capacitor plate is smaller than the distance between the inspection mass and the second capacitor plate, and the second position range is the position of the inspection mass when the distance between the inspection mass and the first capacitor plate is larger than the distance between the inspection mass and the second capacitor plate; the position of the inspection mass is the distance between the center of the inspection mass and the axis of symmetry of the two capacitor plates.

6. The electrostatic accelerometer according to claim 5, characterized in that The range of the control zero position adjustment module to adjust the control zero position is: d0 is the distance between the outer edge of the test mass and the two capacitor plates when the test mass is arranged symmetrically relative to the two capacitor plates.

7. The electrostatic accelerometer according to claim 5 or 6, characterized in that: Let the control zero position be x cmd , the range a of the electrostatic accelerometer under the control zero position mea for: Among them, V f is the feedback voltage used to drive the test mass to reach the control zero position x cmd ;H a To provide feedback voltage V f The transfer function of the feedback actuator; ω e is the angular frequency corresponding to the electrostatic stiffness of the electrostatic accelerometer.

8. The electrostatic accelerometer according to claim 7, characterized in that When the control zero position x cmd In the first position range, x cmd Greater than 0; when the control zero position x cmd In the second position range, x cmd Less than 0.

9. An electronic device, characterized in that: include: at least one memory for storing a computer program; At least one processor is used to execute the program stored in the memory. When the program stored in the memory is executed, the processor is used to execute the method according to any one of claims 1 to 4.

Images