Accelerometer comprising a rectangular coil and a rectangular pole piece

Abstract

The invention is entitled "Accelerometer Including Rectangular Coil and Rectangular Pole Piece." The present disclosure relates to devices, systems, and techniques for determining acceleration. For example, an accelerometer system includes a proof mass, a pole piece connected to the proof mass, and a coil disposed around the pole piece and connected to the proof mass, where the coil is rectangular in shape. Additionally, the accelerometer system includes circuitry configured to transmit an electrical signal to the coil to maintain the proof mass at a null position and to determine a current value corresponding to the electrical signal. Additionally, the circuitry is configured to identify an acceleration of the accelerometer system based on the current value.

Description

Technical Field

[0001] This disclosure relates to accelerometers. Background Technology

[0002] Accelerometers function by detecting the displacement of a test mass under inertial forces. Some accelerometers include a capacitive pickup system. For example, a conductive material (e.g., a capacitor plate) may be disposed on the upper surface of the test mass, and a similar conductive material may be disposed on the lower surface of the test mass. An acceleration or force applied along the sensing axis of the accelerometer causes the test mass to deflect upward or downward, thereby changing the distance (e.g., capacitance gap) between the pickup capacitor plate and the upper and lower non-moving components. This change in capacitance gap causes a change in the capacitance of the capacitor element, which represents the displacement of the test mass along the sensing axis. The change in capacitance can be used as a displacement signal, which can be applied to a servo system including one or more electromagnets (e.g., a force rebalancing coil) to return the test mass to a zero or stationary position. Summary of the Invention

[0003] Generally, this disclosure relates to apparatus, systems, and techniques for determining the acceleration of one or more devices. For example, an electromagnetic accelerometer can prevent displacement of a test mass by transmitting current to a coil, thereby inducing a Lorentz force to prevent displacement of the test mass relative to one or more non-moving components. For example, magnetic flux can form a loop between the pole shoes, the coil, and the non-moving components. This magnetic flux and the current flowing through the coil can induce a servo effect, preventing displacement of the test mass relative to one or more non-moving components. A relationship can exist between the magnitude of the current and the acceleration of the test mass along the sensing axis of the accelerometer, allowing processing circuitry to calculate the acceleration based on the magnitude of the electrical signal transmitted to the coil.

[0004] In some cases, the pole piece is rectangular in shape, and the coil can be arranged around the pole piece such that the pole piece passes through the center of the coil. The coil can also be rectangular in shape. Therefore, the magnitude of the magnetic field can be constant in the region between the first side of the pole piece and the non-moving member. For example, a rectangular pole piece includes four sides. The magnitude of the magnetic field at the first side of the pole piece can be substantially the same as the magnitude of the magnetic field at a first distance outward from the first side of the pole piece. Maintaining a constant magnetic field between the pole piece and the non-moving member is advantageous, so that movement of the coil relative to the pole piece does not affect the Lorentz force preventing displacement of the test mass. That is, compared to an accelerometer with a variable magnetic field between the pole piece and the non-moving member, an accelerometer with a constant magnetic field between the pole piece and the non-moving member can more accurately determine the acceleration of the test mass along the sensing axis.

[0005] In some examples, the accelerometer system includes a test mass and pole shoes, wherein the pole shoes are connected to the test mass. Additionally, the accelerometer system includes a coil disposed around the pole shoes, wherein the coil is connected to the test mass, and wherein the coil is rectangular in shape. Furthermore, the accelerometer system includes circuitry configured to transmit an electrical signal to the coil to hold the test mass at zero position, determine a current value corresponding to the electrical signal, and identify the acceleration of the accelerometer system based on the current value.

[0006] In some examples, the method includes transmitting an electrical signal to a coil via circuitry of the accelerometer system to hold a test mass at zero position. The accelerometer system includes a test mass, pole shoes, and a coil, wherein the pole shoes are connected to the test mass and the coil is disposed around the pole shoes; wherein the coil is connected to the test mass and is rectangular in shape. Additionally, the accelerometer system includes circuitry. The method also includes determining a current value corresponding to the electrical signal via the circuitry, and identifying the acceleration of the accelerometer system via the circuitry based on the current value.

[0007] In some examples, the accelerometer system includes a coil arranged around the pole shoe, connected to a test mass, and wherein the coil is rectangular in shape. Additionally, the accelerometer system includes circuitry configured to transmit an electrical signal to the coil to hold the test mass at zero position, determine a current value corresponding to the electrical signal, and identify the acceleration of the accelerometer system based on that current value.

[0008] The present invention is intended to provide an overview of the subject matter described herein. It is not intended to provide an exclusive or exhaustive description of the systems, apparatus, and methods detailed in the following drawings and specification. Further details of one or more examples of the present disclosure are set forth in the following drawings and specification. Other features, objects, and advantages will be apparent from the specification and drawings, as well as from the claims. Attached Figure Description

[0009] Figure 1 This is a block diagram illustrating an accelerometer system according to one or more technologies of this disclosure.

[0010] Figure 2 This is a conceptual diagram showing a side cross-sectional view of an accelerometer system according to one or more technologies of this disclosure.

[0011] Figure 3 This is a conceptual diagram showing a top cross-sectional view of an accelerometer system according to one or more technologies of this disclosure.

[0012] Figure 4 This is a conceptual diagram illustrating an electrical signal traveling through a coil and a magnetic flux emitted by a pole shoe according to one or more techniques of this disclosure.

[0013] Figure 5 This is a conceptual diagram illustrating the magnetic field strength across the entire cross-section of an accelerometer system according to one or more techniques of this disclosure.

[0014] Figure 6 This is a conceptual diagram showing a perspective view of an accelerometer according to one or more technologies disclosed herein.

[0015] Figure 7 This is a flowchart illustrating an exemplary operation of determining acceleration using an electromagnetic accelerometer according to one or more techniques of this disclosure.

[0016] Similar reference characters are used to denote similar elements throughout the specification and drawings. Detailed Implementation

[0017] This disclosure relates to apparatus, systems, and techniques for determining the acceleration of an object using an accelerometer system. For example, the accelerometer system may be an electromagnetic accelerometer system configured to accurately measure acceleration values. The electromagnetic accelerometer system uses a combination of electrical and magnetic signals to determine the acceleration of an object. For example, the accelerometer system may include magnetic pole shoes, an electric coil, a non-moving member, and a test mass. Magnetic flux can travel from the pole shoes through the coil to the non-moving member and back to the pole shoes. Current can flow through the coil. The accelerometer system can generate a Lorentz force based on the magnetic flux and current, which represents a servo effect preventing displacement of the test mass.

[0018] In some cases, the accelerometer system is configured to measure the acceleration of an object in real time or near real time, allowing processing circuitry to analyze the object's acceleration over a time period to determine the object's positional displacement during that period. For example, the accelerometer system may be part of an inertial navigation system (INS) used to track the object's position based at least in part on its acceleration. Alternatively, the accelerometer system may be positioned on or within the object, causing it to accelerate along with the object. Thus, when the object accelerates, the accelerometer system (including a mass sensing block) accelerates along with the object. Since acceleration over time is the derivative of velocity over time, and velocity over time is the derivative of position over time, in some cases, the processing circuitry may be configured to determine the object's positional displacement by performing a double integral of the object's acceleration over a time period. Determining the object's position using an accelerometer system positioned on the object without using an external navigation system (e.g., a Global Navigation Satellite System (GNSS)) can be termed "dead reckoning."

[0019] To more accurately track the position of an object using an accelerometer system, it may be beneficial to improve the quality of the acceleration values ​​determined by the accelerometer system. For example, the accelerometer system can be configured to determine acceleration along a sensing axis perpendicular to the plane of the test mass block. When the accelerometer system is positively accelerating according to a vector comprising at least one component parallel to the sensing axis and one component perpendicular to the sensing axis, the accelerometer system can accurately determine the magnitude of the component parallel to the sensing axis.

[0020] Forces perpendicular to the sensing axis of the accelerometer system may be referred to herein as “lateral” forces. The accelerometer system can prevent the formation of lateral forces that adversely affect the accuracy of the accelerometer system's acceleration measurements. For example, the pole piece may be located within the center of the coil. In some examples, the coil is shaped like a rectangle with a rectangular opening at its center, and the pole piece has a rectangular cross-section such that it is fitted through the rectangular opening of the coil. In some examples, gaps may exist between the pole piece and the coil on each side of the pole piece. For example, because the pole piece has a rectangular cross-section, it may include a first side, a second side, a third side, and a fourth side. Lateral forces (e.g., vibrational forces) may temporarily cause the coil to move relative to the pole piece, for example, moving the coil closer to the first side of the pole piece and further away from the second side.

[0021] Because the pole shoes are rectangular, the magnetic field on each of the four sides of the pole shoes remains constant as the coil moves away from the pole shoes. Thus, movement of the coil relative to the pole shoes may not affect the magnitude of the Lorentz force generated by the accelerometer system. For example, even if the coil moves laterally relative to the pole shoes, the magnitude of the magnetic field flowing across the coil from the pole shoes will remain constant. The Lorentz force represents the cross product of the magnetic field across the coil and the current flowing through the coil. Therefore, since the magnetic field across the coil remains constant even when the coil moves laterally relative to the pole shoes, lateral movement of the coil may not affect the magnitude of the Lorentz force.

[0022] Figure 1 This is a block diagram illustrating an accelerometer system 100 according to one or more technologies of this disclosure. Figure 1 As shown, the accelerometer system 100 includes a processing circuit 102, a test mass block 104, a first pole shoe 106A, a second pole shoe 106B (collectively referred to as "pole shoe 106"), a first non-moving component 108A, a second non-moving component 108B (collectively referred to as "non-moving component 108"), a first coil 110A, a second coil 110B (collectively referred to as "coil 110"), a first sensor 112A, and a second sensor 112B (collectively referred to as "sensor 112").

[0023] The accelerometer system 100 is configured to determine the relationship between an object and its surroundings based on the magnitude of one or more electrical signals transmitted to the coil 110. Figure 1(Not shown) The associated acceleration, this electrical signal prevents the inspection mass 104 from shifting from zero position. For example, a first sensor 112A may be configured to generate a first sensing signal indicating the size of the gap between the inspection mass 104 and the first non-moving member 108A; and a second sensor 112B may be configured to generate a second sensing signal indicating the size of the gap between the inspection mass 104 and the second non-moving member 108B. The processing circuit 102 may generate a first electrical signal for transmission to the first coil 110A based on the first sensing signal, and may generate a second electrical signal for transmission to the second coil 110B based on the second sensing signal. The first and second electrical signals may generate one or more Lorentz forces to prevent the inspection mass 104 from shifting from zero position.

[0024] The Lorentz force represents the force caused by the interaction of an electric field and a magnetic field. For example, the Lorentz force can be defined by the cross product of the electric and magnetic fields, where the direction of the Lorentz force depends on the directions of the electric and magnetic fields, and the magnitude of the Lorentz force depends on the magnitudes of the electric and magnetic fields.

[0025] Processing circuitry 102 may include one or more processors configured to implement functions and / or processing instructions for execution within accelerometer system 100. For example, processing circuitry 102 may be able to process instructions stored in memory. Processing circuitry 102 may include, for example, a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or equivalent discrete or integrated logic circuitry, or a combination of any of the foregoing devices or circuits. Therefore, processing circuitry 102 may include any suitable structure, whether in hardware, software, firmware, or any combination thereof, to perform the functions described herein for processing circuitry 102.

[0026] Memory ( Figure 1 (Not shown) can be configured to store information within the accelerometer system 100 during operation. The memory may include a computer-readable storage medium or a computer-readable storage device. In some examples, the memory includes one or more of short-term memory or long-term memory. The memory may include, for example, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), magnetic disk, optical disk, flash memory, or electrically programmable memory (EPROM) or electrically erasable programmable memory (EEPROM). In some examples, the memory is used to store program instructions executed by the processing circuitry 102.

[0027] Processing circuit 102 can generate a first electrical signal and a second electrical signal as part of one or more negative feedback loops that hold the inspection mass block 104 at a zero position. Processing circuit 102, first coil 110A, and first sensor 112A represent components of the first negative feedback loop. The first negative feedback loop can maintain the width of the gap between the inspection mass block 104 and the first non-moving member 108A at a first zero width. For example, the first sensor 112A can generate a first sensing signal indicating a capacitance value. The capacitance value is associated with the width of the gap between the inspection mass block 104 and the first non-moving member 108A, and the first sensing signal is transmitted to processing circuit 102. Processing circuit 102 can generate a first electrical signal based on the first sensing signal and transmit the first electrical signal to first coil 110A to maintain the capacitance value of the first sensing signal at a first zero capacitance value. By generating the first electrical signal to maintain the capacitance value of the first sensing signal at a first zero capacitance value, processing circuit 102 maintains the width of the gap between the inspection mass block 104 and the first non-moving member 108A at a first zero width.

[0028] Processing circuit 102, second coil 110B, and second sensor 112B represent components of a second negative feedback loop. The second negative feedback loop maintains the width of the gap between the test mass block 104 and the second non-moving member 108B at a second zero width. For example, the second sensor 112B can generate a second sensing signal indicating a second capacitance value. The capacitance value is associated with the width of the gap between the test mass block 104 and the second non-moving member 108B, and the second sensing signal is transmitted to processing circuit 102. Processing circuit 102 can generate a second electrical signal based on the second sensing signal and transmit the second electrical signal to second coil 110B to maintain the capacitance value of the second sensing signal at a second zero capacitance value. By generating a second electrical signal to maintain the second capacitance value of the second sensing signal at a second zero capacitance value, processing circuit 102 maintains the width of the gap between the test mass block 104 and the second non-moving member 108B at a second zero width.

[0029] In addition, by keeping the width of the gap between the inspection mass block 104 and the first non-moving member 108A at a first zero width and the width of the gap between the inspection mass block 104 and the second non-moving member 108B at a second zero width, the processing circuit 102 can keep the position of the inspection mass block 104 relative to the non-moving member 108 at zero.

[0030] As the acceleration of the accelerometer system 100 changes along the sensing axis, the final acceleration force applied to the test mass 104 can change. Therefore, the processing circuit 102 can change the magnitude of the first electrical signal transmitted to the first coil 110A and the magnitude of the second electrical signal transmitted to the second coil 110B to prevent displacement of the test mass 104 relative to the non-moving member 108. In one example, the acceleration along the sensing axis can increase from a first acceleration value to a second acceleration value. The processing circuit 102 can change the magnitude of the first electrical signal and the magnitude of the second electrical signal to account for the change in acceleration, such that the test mass 104 remains at zero relative to the non-moving member 108. The processing circuit 102 can determine the acceleration of the accelerometer system 100 along the sensing axis based on the magnitude of the first electrical signal transmitted to the first coil 110A and the magnitude of the second electrical signal transmitted to the second coil 110B.

[0031] In some examples, the magnitude of the first electrical signal transmitted to the first coil 110A is proportional to the acceleration along the sensing axis. In some examples, the magnitude of the second electrical signal transmitted to the second coil 110B is proportional to the acceleration along the sensing axis. Thus, an increase in the magnitude of the first electrical signal can correspond to an increase in the acceleration along the sensing axis, and an increase in the magnitude of the second electrical signal can correspond to an increase in the acceleration along the sensing axis. Alternatively, a decrease in the magnitude of the first electrical signal can correspond to a decrease in the acceleration along the sensing axis, and a decrease in the magnitude of the second electrical signal can correspond to a decrease in the acceleration along the sensing axis.

[0032] The accelerometer system 100 may include a first flux loop and a second flux loop. The first flux loop may include a first pole shoe 106A, a first non-moving member 108A, and a first coil 110A. Within the first flux loop, a first magnetic flux may travel from the first pole shoe 106A through the first coil 110A to the first non-moving member 108A. The first magnetic flux then travels through the first non-moving member 108A back to the first pole shoe 106A. In some examples, the first pole shoe 106A may include a first magnet that generates the first magnetic flux. The second flux loop may include a second pole shoe 106B, a second non-moving member 108B, and a second coil 110B. Within the second flux loop, a second magnetic flux may travel from the second pole shoe 106B through the second coil 110B to the second non-moving member 108B. The second magnetic flux then travels through the second non-moving member 108B back to the second pole shoe 106B. In some examples, the second pole shoe 106B may include a second magnet that generates a second magnetic flux.

[0033] Accelerometer system 100 can represent a servo system that uses a Lorentz force parallel to the sensing axis to counteract acceleration along the sensing axis. For example, if accelerometer system 100 accelerates along the sensing axis, the acceleration can apply an accelerating force to test mass 104, wherein the accelerating force is applied to test mass 104 in the opposite direction to the acceleration of accelerometer system 100. Processing circuit 102 transmits a first electrical signal to first coil 110A and a second electrical signal to second coil 110B to generate one or more Lorentz forces to counteract the accelerating force generated by acceleration along the sensing axis. That is, one or more Lorentz forces are applied to test mass 104 in the opposite direction to the accelerating force, such that test mass 104 does not shift from zero position due to the accelerating force. The magnitude of the accelerating force varies based on the change in the magnitude of acceleration along the sensing axis. Therefore, in order to prevent the inspection mass block 104 from shifting from the zero position, the processing circuit 102 changes the value of the first electrical signal transmitted to the first coil 110A and the value of the second electrical signal transmitted to the second coil 110B, so as to change the value of one or more Lorentz forces that counteract the acceleration signal.

[0034] The Lorentz force is a force generated by the interaction between an electric field and a magnetic field. As discussed above, the accelerometer system 100 includes a first magnetic flux loop and a second magnetic flux loop. The first magnetic flux loop includes a channel for a first magnetic flux from pole shoe 106A through a first coil 110A to a first non-moving member 108A. A first electrical signal flows through the first coil 110A. The first magnetic flux and the first electrical signal cause a first Lorentz force to be applied to the test mass 104 in the opposite direction to the accelerating force applied to the detection mass 104 due to acceleration along the sensing axis. Additionally, the second magnetic flux loop includes a channel for a second magnetic flux from second pole shoe 106B through a second coil 110B to a second non-moving member 108B. A second electrical signal flows through the second coil 110B. The second magnetic flux and the second electrical signal cause a second Lorentz force to be applied to the test mass 104 in the opposite direction to the accelerating force applied to the detection mass 104 due to acceleration along the sensing axis.

[0035] In some examples, the pole shoe 106 may be square in shape, and the coil 110 may be square in shape, such that a corresponding opening in the coil 110 is configured to receive the pole shoe 106. For example, the first coil 110A may include a first opening to receive the first pole shoe 106A, which has a square cross-section. The second coil 110B may include a second opening to receive the second pole shoe 106B, which also has a square cross-section. As discussed above, the accelerometer system 100 includes a first flux loop and a second flux loop. As part of the first flux loop, a first magnetic flux may flow from each of the four sides of the first pole shoe 106A.

[0036] Since the cross-section of the first pole piece 106A is rectangular, the magnitude of the magnetic field in the first region extending from the first side of the first pole piece 106A can be uniform, the magnitude of the magnetic field in the second region extending from the second side of the first pole piece 106A can be uniform, the magnitude of the magnetic field in the third region extending from the third side of the first pole piece 106A can be uniform, and the magnitude of the magnetic field in the fourth region extending from the fourth side of the first pole piece 106A can be uniform. The first region extends from the first side of the first pole piece 106A to the first non-moving member 208A, which means that the magnetic field in the space between the first side of the first pole piece 106A and the first non-moving member 208A is uniform. The second region extends from the second side of the first pole piece 106A to the first non-moving member 208A, which means that the magnetic field in the space between the second side of the first pole piece 106A and the first non-moving member 208A is uniform. The third region extends from the third side of the first pole piece 106A to the first non-moving member 208A, meaning that the magnetic field in the space between the third side of the first pole piece 106A and the first non-moving member 208A is uniform. The fourth region extends from the fourth side of the first pole piece 106A to the first non-moving member 208A, meaning that the magnetic field in the space between the fourth side of the first pole piece 106A and the first non-moving member 208A is uniform.

[0037] Since the cross-section of the second pole piece 106B is rectangular, the magnitude of the magnetic field in the first region extending from the first side of the second pole piece 106B can be uniform, the magnitude of the magnetic field in the second region extending from the second side of the second pole piece 106B can be uniform, the magnitude of the magnetic field in the third region extending from the third side of the second pole piece 106B can be uniform, and the magnitude of the magnetic field in the fourth region extending from the fourth side of the second pole piece 106B can be uniform. The first region extends from the first side of the second pole piece 106B to the second non-moving member 208B, which means that the magnetic field in the space between the first side of the second pole piece 106B and the second non-moving member 208B is uniform. The second region extends from the second side of the second pole piece 106B to the second non-moving member 208B, which means that the magnetic field in the space between the second side of the second pole piece 106B and the second non-moving member 208B is uniform. The third region extends from the third side of the second pole piece 106B to the second non-moving member 208B, meaning that the magnetic field in the space between the third side of the second pole piece 106B and the second non-moving member 208B is uniform. The fourth region extends from the fourth side of the second pole piece 106B to the second non-moving member 208B, meaning that the magnetic field in the space between the fourth side of the second pole piece 106B and the second non-moving member 208B is uniform.

[0038] Lateral movement can cause the coil to be displaced relative to the corresponding pole piece. These lateral movements can, for example, cause the first coil 110A to move laterally relative to the first pole piece 106A. In some examples, the first coil 110A extends through a first region from a first side of the first pole piece 106A to a first non-movable member 208A, a second region from a second side of the first pole piece 106A to the first non-movable member 208A, a third region from a third side of the first pole piece 106A to the first non-movable member 208A, and a fourth region from a fourth side of the first pole piece 106A to the first non-movable member 208A. In some examples, the lateral movement of the coil 110A causes it to move closer to the pole piece 106A in the first region and further away from the pole piece 106A in the second region. In at least some of these examples, the magnetic field across the first coil 110A remains unchanged because the magnetic field is uniform in both the first and second regions.

[0039] Figure 2 This is a conceptual diagram showing a side cross-sectional view of an accelerometer system 200 according to one or more technologies of this disclosure. Figure 2 As shown, the accelerometer system 200 includes a test mass assembly 203, a first pole shoe 206A, a second pole shoe 206B (collectively referred to as "pole shoe 206"), a first non-moving member 208A, a second non-moving member 208B (collectively referred to as "non-moving member 208"), a first coil 210A, a second coil 210B (collectively referred to as "coil 210"), a first magnet 220A, and a second magnet 220B (collectively referred to as "magnet 220"). The test mass assembly 203 includes a test mass 204, a first capacitor plate 205A, and a second capacitor plate 205B (collectively referred to as "capacitor plate 205"). Figure 2 In the example, the accelerometer system 200 also includes central raised pads 222A to 222B (collectively referred to as "central raised pad 222"), outer raised pads 224A to 224D (collectively referred to as "outer raised pad 224"), a first frequency band 226A, a second frequency band 226B (collectively referred to as "frequency band 226"), a first capacitor gap 232, and a second capacitor gap 234. Figure 2 In one example, the accelerometer system 200 may include accelerometer supports 214A to 214B (collectively referred to as "accelerometer support 214"), which may be formed by a combination of pole shoes 206, non-moving members 208, and magnets 220. The accelerometer system 200 may be... Figure 1 An example of an accelerometer system 100. The test mass block 204 can be... Figure 1 Example of inspection quality block 104. Pole shoe 206 can be... Figure 1 Example of pole shoe 106. Non-moving component 208 may be Figure 1An example of a non-moving component 108. Coil 110 may be... Figure 1 Example of coil 210.

[0040] Accelerometer system 200 can be configured to sense acceleration along sensing axis 201. For example, accelerometer system 200 can be configured to sense acceleration along sensing axis 201 in a first direction 211. In some cases, accelerometer system 200 determines the magnitude of acceleration along sensing axis 201 in the first direction 211 with real-time or near real-time precision, such that processing circuitry ( Figure 2 (Not shown in the image) Dead reckoning can be used to track the position of the accelerometer system 200. For example... Figure 2 As shown, the test mass assembly 203 is suspended between the first non-movable member 208A and the second non-movable member 208B via a central raised pad 222 and an outer raised pad 224. In some examples, the processing circuitry may receive a first sensing signal indicating the width of the first capacitor gap 232 and a second sensing signal indicating the width of the second capacitor gap 234. The processing circuitry may then transmit a first electrical signal to the first coil 210A and a second electrical signal to the second coil 210B to prevent the test mass 204 from displacing in response to acceleration along the sensing axis 201 of the accelerometer system 200. The magnitudes of the first and second electrical signals may be correlated with the magnitude of the acceleration.

[0041] Non-movable member 208 may be connected to (e.g., clamped to) the central raised pad 222 and the outer raised pad 224, thereby securing the test mass assembly 203 between the first non-movable member 208A and the second non-movable member 208B. The term "non-movable member" may refer to a member indicating a reference position to which the position of the test mass assembly 203 can be compared. In other words, the position of the test mass assembly 203 may indicate the position of the test mass assembly 203 relative to the non-movable member 208. In some examples, the non-movable member 208 comprises a bimetallic material that may be part of a flux loop. In some examples, the non-movable member 208 may resemble the stator of a variable capacitor.

[0042] In some cases, coil 210 can conduct electricity, allowing electrical signals to flow through it. For example, a first electrical signal can flow through the path of the first coil 210A, and a second electrical signal can flow through the path of the second coil 210B. The path of the first coil 210A can form a square path, and the path of the second coil 210B can also form a square path. Because... Figure 2 This is a cross-sectional view of the accelerometer system 200, showing that the square paths of the first coil 210A and the second coil 210B are not within... Figure 2As shown in the figure, coil 210 extends completely around the outer surface of pole shoe 206, such that a first electrical signal flows around the outer surface of pole shoe 206A through the first coil 210A, and a second electrical signal flows around the outer surface of pole shoe 206B through the second coil 210B.

[0043] Frequency band 226 is a metal element that fastens the first non-movable member 208A to the second non-movable member 208B. In some examples, frequency band 226 may be attached (e.g., with epoxy adhesive) to the non-movable member 208 when it is attached to the test mass block assembly 203 via the central raised pad 222 and the outer raised pad 224. Accelerometer system 200 includes a first capacitance gap 232 and a second capacitance gap 234. The first capacitance gap 232 represents the gap between the first capacitor plate 205A and the first non-movable member 208A, and the second capacitance gap 234 represents the gap between the second capacitor plate 205B and the second non-movable member 208B. The first capacitor plate 205A can generate a first sensing signal indicating a first capacitance value. The first capacitance value is associated with the width of the first capacitance gap 232. The second capacitor plate 205B can generate a second sensing signal indicating a second capacitance value. The second capacitance value is associated with the width of the second capacitance gap 234. Thus, the first capacitor plate 205A can represent... Figure 1 The first sensor 112A and the second capacitor plate 205B can represent Figure 1 The second sensor 112B. Processing circuit ( Figure 2 (Not shown) can receive a first sensing signal and a second sensing signal, and control the electrical signal transmitted to the coil 210 based on the first sensing signal and the second sensing signal.

[0044] In some examples, the zero width of the first capacitor gap 232 may be defined by the widths of the outer raised pad 224 and the central raised pad 222. In some examples, the zero width of the first capacitor gap 232 is in the range of 0.0005 inches to 0.0025 inches. In some examples, the zero width of the second capacitor gap 234 may be defined by the widths of the outer raised pad 224 and the central raised pad 222. In some examples, the zero width of the second capacitor gap 234 is in the range of 0.0005 inches to 0.0025 inches. When the width of the first capacitor gap 232 is at its zero width and the width of the second capacitor gap 234 is at its zero width, the test mass block 204 may be located at zero. That is, the test mass block 204 may be located at zero such that the processing circuitry is configured to determine the acceleration along the sensing axis 201 based on a first electrical signal transmitted to the first coil 210A and a second electrical signal transmitted to the second coil 210B.

[0045] In some examples, the first capacitor gap 232 may have a first capacitance value. The processing circuitry can detect the first capacitance value of the first capacitor gap 232, which can be detected and used in a closed-loop differential capacitor configuration to determine the acceleration of the accelerometer system 200. Additionally, the second capacitor gap 234 may have a second capacitance value. The processing circuitry can detect the second capacitance value of the second capacitor gap 234, which can be detected and used in a closed-loop differential capacitor configuration to determine the acceleration of the accelerometer system 200. In some examples, an increase in the width of the first capacitor gap 232 and a decrease in the width of the second capacitor gap 234 can indicate the acceleration of the accelerometer system 200 in a first direction 211A. Conversely, an increase in the width of the second capacitor gap 234 and a decrease in the width of the first capacitor gap 232 can indicate the acceleration of the accelerometer system 200 in a second direction 211B. The processing circuitry can transmit a first electrical signal to the first coil 210A and a second electrical signal to the second coil 210B to counteract the displacement of the test mass block 204 from its zero position. The magnitudes of the first and second electrical signals can be correlated with the magnitude of the acceleration along the sensing axis 201.

[0046] Magnet 220 is a magnet used to provide a magnetic field to drive the magnetic circuit of magnet 220, pole shoe 206, coil 210, and non-moving member 208. In some examples, magnet 220 may be made of AlNiCo alloy, samarium-cobalt, neodymium-iron-boron, or other such materials. In some examples, magnet 220 may receive forces and / or stresses transmitted from non-moving member 208 due to the construction of accelerometer system 200. In some examples, magnet 220 may be part of a null metering configuration of accelerometer system 200.

[0047] The pole shoe 206 is a magnetic structure that enables the magnetic field of the magnet 220 to be focused and drive the magnetic circuit of the magnet 220, pole shoe 206, coil 210, and non-moving member 208. For example, the pole shoe 206 may be a magnetic structure that allows the magnetic field of the magnet to bend and flow through the coil 210. In these examples, by allowing the magnetic field of the magnet 220 to pass through the coil 210, the magnetic field of the magnet 220 can enter the non-moving member 208 and surround the opposite side of the magnet through the non-moving member 208, and flow back to the pole shoe through the magnet, completing the magnetic circuit. For example, the first magnetic circuit may represent a magnetic flux loop in which a first magnetic flux is transferred from the first magnet 220A to the first pole shoe 206A. The first magnetic flux travels from the first pole shoe 206A through the first coil 210A to the first non-moving member 208A. Then, the first magnetic flux travels back to the first magnet 220A through the first non-moving member 208A to complete the first magnetic circuit. The second magnetic circuit can represent a magnetic flux loop, wherein a second magnetic flux is transferred from the second magnet 220B to the second pole shoe 206B. The second magnetic flux travels from the second pole shoe 206B through the second coil 210B to the second non-moving member 208B. Then, the second magnetic flux travels back to the second magnet 220B through the second non-moving member 208B to complete the second magnetic circuit.

[0048] In some examples, the pole piece 206 may be part of the zero-measurement configuration of the accelerometer system 200. In some examples, the pole piece 206 may be made of a magnetically permeable material, such as Invar alloy, nickel-iron high-permeability alloy, iron-nickel alloy, or other such materials.

[0049] In some examples, the accelerometer system 200 may include coils 210 attached to each side of the test mass. In some examples, the accelerometer system 200 may include processing circuitry. Figure 2 (Not shown in the diagram), the circuit is configured to transmit a first electrical signal and a second electrical signal to coil 210 to position the test mass 204 at zero. In some examples, as the accelerometer system 200 accelerates along the sensing axis 201, the processing circuit may increase the current magnitude of the first electrical signal and the current magnitude of the second electrical signal to hold the test mass 204 at zero. In this example, the current magnitudes of the first and second electrical signals are proportional to the magnitude of the acceleration along the sensing axis 201.

[0050] Preventing the inspection mass block 204 from shifting from zero may be referred to herein as a "servo effect." In some examples, the processing circuitry can cause one or more Lorentz forces to counteract the acceleration force applied to the inspection mass block 204, preventing the inspection mass block 204 from moving from zero. This means that the processing circuitry is configured to adjust one or more Lorentz forces in real time or nearly real time, such that one or more Lorentz forces counteract the acceleration force applied to the inspection mass block 204 at any given time, thereby continuously holding the inspection mass block 204 at zero. The processing circuitry can generate the electrical signals required to produce one or more Lorentz forces based on a first sensing signal received from the first capacitor plate 205A and a second sensing signal received from the second capacitor plate 205B.

[0051] Coil 210 can be mounted on either side of the test mass 204 of the test mass assembly 203. In some examples, the processing circuitry can modify the current from coil 210 to the servo test mass 204 to maintain a zero position. Any acceleration of the accelerometer system 200 will instantaneously move the test mass of the test mass assembly 203 out of the zero plane, and the increase in current required to hold the test mass 204 at zero is proportional to the magnitude of the acceleration of the accelerometer system 200 along the sensing axis 201.

[0052] although Figure 2 An accelerometer system 200 is shown with capacitor plates and coils on both sides of the test mass assembly 203 to form a combined capacitance pickup system. However, it should be understood that the accelerometer system 200 may have capacitor plates and coils only on one side of the test mass assembly 203. Similarly, although... Figure 2 An accelerometer system 200 is shown with non-movable members on both sides of the test mass assembly 203 to form a combined capacitive pickup system. However, it should be understood that the accelerometer system 200 may have non-movable members and capacitor plates on the same side of the test mass assembly 203.

[0053] Figure 3 This is a conceptual diagram showing a top cross-sectional view of an accelerometer system 300 according to one or more technologies of this disclosure. Figure 3 As shown, the accelerometer system 300 includes a test mass block 304, a capacitor plate 305, a pole shoe 306, a non-moving component 308, a coil 310, and frequency bands 326A to 326D (collectively referred to as "frequency band 326"). The accelerometer system 300 can be... Figure 2 An example of an accelerometer system 200. The test mass block 304 can be... Figure 2 Example of inspection quality block 204. Capacitor plate 305 can be... Figure 2 Example of the first capacitor plate 205A. The pole piece 306 can be... Figure 2 An example of the first pole shoe 206A. The non-moving member 308 may be... Figure 2 An example of the first non-movable component 208A. Coil 310 may be... Figure 2 An example of the first coil 210A. In some examples, the sensing axis 301 of the accelerometer system 300 extends into... Figure 3 The accelerometer system 300 can sense the entry into or from that page. Figure 3 The acceleration of the page and sensing from that Figure 3 The acceleration displayed on the page. In some examples, plane 348 represents the constraint. Figure 2 The cut plane of the side section view.

[0054] In response to the acceleration along the sensing axis 301 of the accelerometer system 300, the processing circuit of the accelerometer system 300 ( Figure 3 (Not shown in the image) can transmit electrical signal 342 to coil 310. For example... Figure 3 As shown, the electrical signal 342 travels clockwise through the path of coil 310. Additionally, magnetic flux 346 is transmitted outward from pole shoe 306 to non-moving member 308 via coil 310. Coil 310 includes four sides. Figure 3 As shown, for each of the four sides of coil 310, electrical signal 342 flows in a direction perpendicular to the direction of magnetic flux 346. The electrical signal 342 flowing perpendicular to the direction of magnetic flux 346 can generate... Figure 3 The Lorentz force that guides the page outwards. This Lorentz force can counteract the force applied to the guide into. Figure 3 The acceleration force of the inspection mass block 304 on the page. The direction of the Lorentz force generated by the electrical signal 342 (e.g., into or out of the page) may depend on the direction of the electrical signal 342 within the coil 310. For example, when the electrical signal 342 flows through the coil 310 in a clockwise direction, the generated Lorentz force is directed outward from the page. Alternatively, when the electrical signal 342 flows through the coil 310 in a counterclockwise direction, the generated Lorentz force is directed into the page.

[0055] Figure 4 This is a conceptual diagram illustrating an electrical signal traveling through coil 410 and a magnetic flux emitted by pole shoe 406 according to one or more techniques of this disclosure. Figure 4 As shown, electrical signals 442A to 442D (collectively referred to as "electrical signals 442") travel clockwise through coil 410. Coil 410 includes a first side 452A, a second side 452B, a third side 452C, and a fourth side 452D (collectively referred to as "side 452"). Coil 410 may be part of an accelerometer system that senses acceleration along sensing axis 401. Figure 4 The page extends outwards and extends to Figure 4On the page. Magnetic flux 454A can travel from pole shoe 406 through side 452A of coil 410, magnetic flux 454B can travel from pole shoe 406 through side 452B of coil 410, magnetic flux 454C can travel from pole shoe 406 through side 452C of coil 410, and magnetic flux 454D can travel from pole shoe 406 through side 452A of coil 410. D The 406 extreme boot is available as... Figure 1 Extreme boots 406, Figure 2 Extreme boots 406 and Figure 3 Examples of any one or more of the pole shoes 306. Coil 410 may be... Figure 1 Coil 110, Figure 2 Coil 210 and Figure 3 Examples of any one or more of the coils 310.

[0056] Processing circuit ( Figure 4 (Not shown in the image) Electrical signal 442 can be transmitted to coil 410, causing electrical signal 442 to travel clockwise around the path of coil 410. Magnetic flux 454A to 454D (collectively referred to as "magnetic flux 454") travels outward from pole shoe 406, such that magnetic flux 454 is orthogonal to electrical signal 442. For example... Figure 4 As shown, electrical signal 442A is perpendicular to magnetic flux 454A, electrical signal 442B is perpendicular to magnetic flux 454B, electrical signal 442C is perpendicular to magnetic flux 454C, and electrical signal 442D is perpendicular to magnetic flux 454D. Therefore, electrical signal 442 is perpendicular to the magnetic flux 454 on each of the sides 452A to 452D of coil 410, thereby... Figure 4 The page generates a Lorentz force outwards, where this Lorentz force is parallel to the sensing axis 401. In an example where the electrical signal 442 travels a counterclockwise path around the coil 410, this could potentially generate a Lorentz force... Figure 4 On the page.

[0057] like Figure 4 As shown, the cross-sectional shape of the pole shoe 406 is square, and the cross-sectional shape of the coil 410 is a square with a square opening, so that the pole shoe 406 fits the square opening of the coil 410. The square shape of the cross-section of the pole shoe 406 is beneficial for accurately measuring the acceleration along the sensing axis 401. For example, by emitting magnetic flux 454 from the straight edge of the pole shoe with a square cross-section, the density of magnetic flux 454A is uniform. That is, the magnitude of the magnetic field is substantially the same at any point within magnetic flux 454A, substantially the same at any point within magnetic flux 454B, substantially the same at any point within magnetic flux 454C, and substantially the same at any point within magnetic flux 454D.

[0058] The Lorentz force represents the cross product of an electric field and a magnetic field perpendicular to that electric field. Therefore, the magnitude of the Lorentz force depends on the magnitudes of both the electric and magnetic fields. It may be advantageous for the electric field, represented by magnetic flux 454, to be uniform in magnitude, so that lateral displacement of coil 410 relative to pole shoe 406 does not affect the magnitude of the Lorentz force representing the cross product of electrical signal 442 and magnetic flux 454. In one or more examples where the pole shoe has a circular cross-section and no straight edges, the magnetic field emitted by the pole shoe will extend non-uniformly outward from the pole shoe. For example, the strength of the magnetic field will decrease with distance from the circular pole shoe. This means that movement of the coil positioned around the circular pole shoe can affect the magnitude of the resulting Lorentz force, thereby affecting the measured acceleration. Therefore, an accelerometer system 400 including pole shoes with polygonal (e.g., square, rectangular, triangular, or other polygonal) cross-sections can determine acceleration more accurately than an accelerometer system 400 including pole shoes with cross-sections having one or more circular edges.

[0059] One or more techniques described herein allow the accelerometer system 400 to accurately determine acceleration along the sensing axis 401 under conditions where the accelerometer system 400 is based on vector vibrations not parallel to the sensing axis 401. For example, vibrations along an axis not parallel to the sensing axis 401 can cause the coil 410 to move "laterally" relative to the pole shoe 406. These lateral movements cause the coil 410 to move relative to the pole shoe 406 such that, compared to before the lateral movement, the coil 410 traverses a different portion of the magnetic flux 454. Because the magnitude of the magnetic field of the magnetic flux 454 is... Figure 4 The region of magnetic flux 454 shown is uniform, and lateral movement of coil 410 relative to pole shoe 406 may not affect the magnitude of the Lorentz force generated by electrical signal 442 and magnetic flux 454.

[0060] Figure 5 This is a conceptual diagram illustrating the magnetic field strength across a cross-section of an accelerometer system 500 according to one or more technologies of this disclosure. The accelerometer system 500 includes non-moving components 508A to 508B (collectively referred to as "non-moving components 508"), coils 510A to 510B (collectively referred to as "coils 510"), and frequency bands 526 to 526B (collectively referred to as "frequency band 526"). The accelerometer system 500 may be... Figure 1 An example of an accelerometer system 100. The non-moving component 508 may be... Figure 1 An example of a non-moving component 108. Coil 510 may be... Figure 1 Example of coil 110. Bandwidth 526 can be... Figure 2 Example of frequency band 226. Figure 5 The diagram shows the strength of the magnetic field based on the darkness of the shadow. Darker shadows indicate a stronger magnetic field, and brighter shadows indicate a weaker magnetic field.

[0061] Gap 560A represents the gap between the non-movable member 508A and the first side of the magnet 520A, the magnet including corresponding pole shoes. Gap 560B represents the gap between the non-movable member 508A and the second side of the magnet 520A. Gap 560C represents the gap between the non-movable member 508B and the first side of the magnet 520B, the magnet including corresponding pole shoes. Gap 560D represents the gap between the non-movable member 508B and the second side of the magnet 520B. (The rest of the text is missing.) Figure 5 As shown, the shading within gaps 560A to 560D is substantially uniform. This means that the movement of coil 510A within gaps 560A and 560B, or the movement of coil 510B within gaps 560C and 560D, will not change the strength of the magnetic field across coil 510A or across coil 510B, respectively. The uniformity of the magnetic field in gap 560 is due to the square shapes of magnet 520A and its corresponding pole piece, and also to the square shapes of magnet 520B and its corresponding pole piece.

[0062] Figure 6 This is a conceptual perspective view illustrating an accelerometer 600 according to one or more technologies of this disclosure. In some cases, the accelerometer 600 may represent... Figures 2 to 5 The accelerometer shown in the cross-section of any of them. Figure 6 As shown, frequency bands 626A to 626C and Figure 6 A fourth frequency band (not shown) secures non-movable components 608A and 608B together. Magnets 620A and 620B are located at the center of the accelerometer 600. Coil 610A is arranged around magnet 620A, and coil 610B is arranged around magnet 620B. Non-movable component 608 may be... Figure 2 An example of a non-moving component 208. Coil 610 may be... Figure 2 Example of coil 210. Magnet 620 may be... Figure 2 Example of magnet 220.

[0063] Figure 7 This is a flowchart illustrating an exemplary operation of determining acceleration using an electromagnetic accelerometer according to one or more techniques of this disclosure. Relative to Figure 1 100 pairs of accelerometer systems Figure 7 To describe. However, Figure 7 The technology can be performed by different components of the accelerometer system 100 or by additional or alternative equipment.

[0064] The processing circuit 102 can receive a first capacitance signal (702) indicating the capacitance value from the first sensor 112A. In some examples, the first sensor 112A may represent a first capacitor plate located on a first side of the inspection mass block 104 (e.g., Figure 2The first capacitor plate 205A). The processing circuit 102 can generate an electrical signal based on the capacitance signal to include a current value (704) that holds the test mass block 104 at zero. The processing circuit 102 can transmit the electrical signal to the first coil 110A (706). In some examples, the processing circuit 102 can transmit the electrical signal to the first coil 110A such that the first coil 110A applies a Lorentz force to the test mass block 104, thereby counteracting the acceleration force applied to the test mass block 104.

[0065] Processing circuit 102 can determine the current value corresponding to the electrical signal (708). Subsequently, processing circuit 102 can identify the acceleration of accelerometer system 100 based on the current value (710). In other words, the strength of the electrical signal required to keep the test mass 104 at zero position is correlated with the acceleration of accelerometer system 100 along the sensing axis.

[0066] In one or more examples, the accelerometer described herein may implement the functions using hardware, software, firmware, or any combination thereof. Those functions implemented in software may be stored as one or more instructions or code on or transmitted via a computer-readable medium and executed by a hardware-based processing unit. The computer-readable medium may include a computer-readable storage medium corresponding to a tangible medium such as a data storage medium, or a communication medium that includes, for example, any medium facilitating the transfer of a computer program from one place to another according to a communication protocol. Thus, a computer-readable medium may generally correspond to: (1) a non-transitory tangible computer-readable storage medium, or (2) a communication medium such as a signal or carrier wave. The data storage medium may be any available medium accessible by one or more computers or one or more processors to retrieve instructions, code, and / or data structures for implementing the techniques described herein.

[0067] Instructions may be executed by or communicatively coupled to one or more processors within the accelerometer. These processors may, for example, include one or more DSPs, general-purpose microprocessors, application-specific integrated circuits (ASICs), FPGAs, or other equivalent integrated or discrete logic circuits. Therefore, the term "processor" as used herein may refer to any of the foregoing structures or any other structure suitable for implementing the techniques described herein. Furthermore, in some aspects, the functionality described herein may be provided within dedicated hardware and / or software modules configured to perform the techniques described herein. Moreover, these techniques may be implemented entirely within one or more circuit or logic elements.

[0068] The techniques disclosed herein can be implemented in various devices or apparatuses including integrated circuits (ICs) or a set of ICs (e.g., chipsets). Various components, modules, or units are described in this disclosure to emphasize functional aspects of a device configured to perform the disclosed techniques, but they do not necessarily need to be implemented by different hardware units. Instead, the various units may be combined with or provided by a collection of interoperable hardware units (including one or more processors as described above) incorporating suitable software and / or firmware.

Claims

1. An accelerometer system, the accelerometer system comprising: Inspect the quality block; Extreme shoe, wherein the extreme shoe is connected to the inspection quality block; A coil, the coil being arranged around the pole shoe, wherein the coil is connected to the inspection mass block, wherein the coil is rectangular in shape, and wherein the cross-section of the pole shoe is rectangular, such that the pole shoe is assembled through a rectangular opening in the coil; A non-movable member, wherein within a magnetic flux loop, magnetic flux travels from the pole shoe through the coil to the non-movable member, wherein the pole shoe and the non-movable member are configured such that the magnitude of the magnetic field in a first region extending from a first side of the first pole shoe is uniform, the magnitude of the magnetic field in a second region extending from a second side of the first pole shoe is uniform, the magnitude of the magnetic field in a third region extending from a third side of the first pole shoe is uniform, and the magnitude of the magnetic field in a fourth region extending from a fourth side of the first pole shoe is uniform. and The circuit is configured as follows: An electrical signal is transmitted to the coil to keep the inspection mass block at zero position; Determine the current value corresponding to the electrical signal; as well as The acceleration of the accelerometer system is identified based on the current value.

2. The accelerometer system according to claim 1, wherein the circuit is configured to: Receive a capacitance signal indicating a capacitance value from a capacitance sensor, wherein the capacitance value is associated with the width of the gap between the test mass block and the non-moving component; and The circuit generates the electrical signal to include a current value and holds the inspection mass block at the zero position by keeping the width of the gap between the inspection mass block and the non-moving member at zero gap width.

3. The accelerometer system according to claim 2, wherein the pole piece is a first pole piece, the coil is a first coil, the electrical signal is a first electrical signal, the current value is a first current value, and the accelerometer system further comprises: A second pole shoe, wherein the second pole shoe is connected to the inspection quality block; and A second coil is disposed around the second pole shoe, wherein the second coil is connected to the test mass block, and wherein the second coil is rectangular in shape. The circuit is further configured as follows: A second electrical signal is transmitted to the second coil to hold the inspection mass block at the zero position; Determine the second current value corresponding to the second electrical signal; as well as The acceleration of the accelerometer system is identified based on the second current value and the first current value.

4. The accelerometer system according to claim 3, wherein the non-moving component is a first non-moving component, the capacitive sensor is a first capacitive sensor, the capacitive signal is a first capacitive signal, the capacitance value is a first capacitance value, the zero gap width is a first zero gap width, and the accelerometer system further comprises: The second non-movable component, The circuit is configured as follows: A second capacitance signal indicating a second capacitance value is received from a second capacitance sensor, wherein the second capacitance value is associated with the width of the gap between the test mass block and the second non-moving component; as well as The circuit generates a second electrical signal to include a second current value, and holds the inspection mass block at the zero position by maintaining the width of the gap between the inspection mass block and the second non-moving member at a second zero gap width.

5. The accelerometer system of claim 1, wherein the circuit is configured to hold the test mass block at the zero position such that the longitudinal axis of the pole shoe remains perpendicular to the plane of the test mass block.

6. The accelerometer system according to claim 5, The accelerometer system is configured such that when the coil is displaced parallel to the plane of the test mass, a first space between the first side of the pole shoe and the coil increases and a second space between the second side of the pole shoe and the coil decreases. The circuit is configured to identify the acceleration as the first space increases and the second space decreases.

7. The accelerometer system of claim 5, wherein the acceleration of the accelerometer system identified by the circuit represents an acceleration perpendicular to the plane of the test mass block.

8. The accelerometer system of claim 1, wherein the circuit is configured to identify the acceleration by calculating the acceleration based on the relationship between the current value and the acceleration, wherein the current value is positively correlated with the acceleration.

9. The accelerometer system according to claim 1, The coil includes a first side, a second side, a third side opposite to the first side, and a fourth side opposite to the second side. The accelerometer system is configured such that the magnetic field at the first side is constant along the length of the first side from a first end to a second end. The accelerometer system is configured such that the magnetic field at the second side is constant along the length of the second side from the first end to the second end. The accelerometer system is configured such that the magnetic field at the third side is constant along the length of the third side from the first end to the second end. The accelerometer system is configured such that the magnetic field at the fourth side is constant along the length of the fourth side from the first end to the second end of the fourth side.

10. An acceleration detection method, the method comprising: An electrical signal is transmitted to a coil via the circuitry of the accelerometer system to hold the test mass block at zero position, wherein the accelerometer system includes: The inspection quality block; Extreme shoe, wherein the extreme shoe is connected to the inspection quality block; The coil is arranged around the pole shoe, wherein the coil is connected to the inspection mass block, wherein the coil is rectangular in shape, and wherein the cross-section of the pole shoe is rectangular, such that the pole shoe is assembled through a rectangular opening in the coil; A non-movable member, wherein within a magnetic flux loop, a first magnetic flux travels from the pole shoe through the coil to the non-movable member, wherein the pole shoe and the non-movable member are configured such that the magnitude of the magnetic field in a first region extending from a first side of the first pole shoe is uniform, the magnitude of the magnetic field in a second region extending from a second side of the first pole shoe is uniform, the magnitude of the magnetic field in a third region extending from a third side of the first pole shoe is uniform, and the magnitude of the magnetic field in a fourth region extending from a fourth side of the first pole shoe is uniform; and The circuit; The circuit determines the current value corresponding to the electrical signal; and The circuit identifies the acceleration of the accelerometer system based on the current value.

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