An angular velocity sensor for eliminating eccentricity of a screw pump pumping unit

Abstract

The application discloses an eccentricity-eliminable angular velocity sensor for a screw pump oil pumping machine, and achieves the purpose of measuring the angular velocity of the screw while eliminating the installation eccentricity on the screw pump oil pumping machine; the angular velocity sensor comprises an open base, three inertial sensors are installed according to specific azimuth angles, a sealing cover for sealing the inertial sensors, fixing bolts for fastening and a Wheatstone bridge circuit matched with the fixing bolts; the application further discloses a method for measuring the eccentricity and calculating the angular velocity by using the sensor; the eccentricity and the angular velocity are measured by the inertial sensors and the Wheatstone bridge circuit, the structure is simple and reliable, the machining precision requirement is not high, and the assembly is simple.

Description

Technical Field

[0001] This invention relates to the field of angular velocity sensor technology, and more specifically to an angular velocity sensor for use in screw pump oil extraction units with an eccentricity that can be eliminated. Background Technology

[0002] Screw pump oil pumps are widely used in domestic oilfields. The screw pump creates periodic sealed cavities through reciprocating rotation. The medium is drawn in under the pressure difference at the suction end and gradually pushed through the sealed chambers to the discharge end as the rotor rotates. Therefore, real-time monitoring of the screw pump's rotation, forming an "Internet of Things" within the oilfield, has significant economic implications for the petroleum industry. However, existing angular velocity sensors are generally difficult to install and cannot adapt to the harsh working environment of open-pit oil wells, hindering their widespread application in oilfields. Furthermore, due to limitations in installation environment and technology, traditional angular velocity sensors are prone to introducing eccentricity errors during installation, and these unavoidable errors affect the angular velocity measurement readings.

[0003] Therefore, developing an angular velocity sensor that can measure and eliminate installation eccentricity is of great value to the development of the petroleum industry. Summary of the Invention

[0004] To overcome the problems existing in the prior art, the present invention aims to provide an angular velocity sensor for screw pump oil pumps that can eliminate eccentricity. By using three inertial sensors distributed at a specific angle, and with the help of a Wheatstone bridge and related calculations, the eccentricity caused by improper installation can be measured simultaneously with the screw angular velocity of the screw pump oil pump, thereby guiding technicians to correct the installation position to eliminate eccentricity.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An eccentricity-eliminating angular velocity sensor for a screw pump oil extraction unit includes an open base 1, three inertial sensors mounted on the open base 1, and sensor sealing covers sealing the three inertial sensors. The three inertial sensors are designated as a first sensor 2-1, a second sensor 2-2, and a third sensor 2-3. The open base 1 has a U-shaped opening and two concentric arcs, with the centers of the two concentric arcs defined as the rotation center. The first sensor 2-1, the second sensor 2-2, and the third sensor 2-3 are all inertial sensors, symmetrically installed at 90°, 180°, and 270° angles to the opening direction of the open base 1, respectively. The first sensor 2-1, the second sensor 2-2, and the third sensor 2-3 are all equidistant from the rotation center. The sensor's sensitive direction is set towards the center of rotation; the first sensor 2-1 includes a first sensitive beam 7-1 and a first strain gauge 3-1, a second strain gauge 3-2, a third strain gauge 3-3, and a fourth strain gauge 3-4 arranged on the first sensitive beam 7-1, wherein the first strain gauge 3-1 and the fourth strain gauge 3-4 are installed on the side closer to the center of rotation, the second strain gauge 3-2 and the third strain gauge 3-3 are installed on the side away from the center of rotation, the first strain gauge 3-1 and the third strain gauge 3-2 are installed at the same end of the first sensitive beam 7-1, and the fourth strain gauge 3-4 and the third strain gauge 3-3 are installed at the same end of the first sensitive beam 7-1; the first strain gauge 2-1 is set to face the center of rotation; the first strain gauge 2-1 includes a first sensitive beam 7-1 and a first strain gauge 3-2, a second strain gauge 3-2, a third strain gauge 3-3, and a fourth strain gauge 3-4; the first strain gauge 2-1 is set to face the center of rotation ...2 is set to face the center of rotation; the first strain gauge 2-3 is set to face the center of rotation; the first strain gauge 2-1 is set to face the center of rotation; the first strain gauge 2-2 is set to face the center of rotation; the first strain gauge 2-3 is set to face the center of rotation; the first strain gauge 2-3 is set to face the center Strain gauge 3-1, second strain gauge 3-2, fourth strain gauge 3-4, and third strain gauge 3-3 are connected clockwise in sequence to form a first Wheatstone bridge 6-1. Strain gauge 3-3, second strain gauge 3-2, fourth strain gauge 3-4, and first strain gauge 3-1 are connected clockwise in sequence to form a second Wheatstone bridge 6-2. The structure of the second sensor 2-2 and the way in which the third Wheatstone bridge 6-3 and the fourth Wheatstone bridge 6-4 are formed are the same as those of the first sensor 2-1. The structure of the third sensor 2-3 and the way in which the fifth Wheatstone bridge 6-5 and the sixth Wheatstone bridge 6-6 are formed are also the same as those of the first sensor 2-1.

[0007] The angular velocity sensor is installed on the screw of the screw pump oil pumping unit. The specific installation method is as follows: first, place the angular velocity sensor on the screw rotating platform of the screw pump oil pumping unit, pass the screw through the U-shaped opening in the middle of the open base 1, and then use screws to tighten and fix the open base 1 to the screw rotating platform.

[0008] If improper installation causes the actual rotation center to deviate from the design rotation center, the deformation voltage caused by centrifugal force and eccentric force is measured by the Wheatstone bridge formed by the strain gauges on the sensitive beam. The effect of eccentricity is eliminated by calculation, and the angular velocity of the rotating screw under test is calculated. At the same time, the eccentricity between the actual rotation center and the design rotation center is measured.

[0009] Preferably, the open base 1 is made of cast iron, which has high strength.

[0010] The method for measuring eccentricity using the angular velocity sensor is as follows:

[0011] Consider the following eccentric rotation: With the rotation center set as the origin, the coordinates of the eccentric rotation center are (x, y). The angular velocity of the open base 1 is ω. The distance from the first sensor 2-1 to the eccentric rotation center is r1, and the angle between r1 and the y-axis is θ1. The distance from the second sensor 2-2 to the eccentric rotation center is r2, and the angle between r2 and the x-axis is θ2. The distance from the third sensor 2-3 to the eccentric rotation center is r3, and the angle between r3 and the y-axis is θ3. Consider the forces acting on the first sensor 2-1: The first sensor 2-1 experiences a centripetal acceleration a.n With eccentric acceleration a τ Together, they work together, including:

[0012] a n =ω 2 r1cos(θ1)

[0013] a τ =ω 2 r1sin(θ1)

[0014] For the first sensor 2-1, the four strain gauges attached to the root of its first sensitive beam 7-1 are connected to form a first Wheatstone bridge 6-1 and a second Wheatstone bridge 6-2, respectively. According to mechanics of materials:

[0015] The strain generated by the first strain gauge 3-1 is

[0016] The strain generated by the second strain gauge 3-2 is

[0017] The strain generated by the third strain gauge 3-3 is

[0018] The strain generated by the fourth strain gauge 3-4 is

[0019] Where ε n ε represents the axial strain of the first sensitive beam 7-1 under centripetal force. τ Let be the tangential strain of the first sensitive beam 7-1 under centripetal force, m be the equivalent mass of the first sensitive beam 7-1, L be the length of the first sensitive beam 7-1, W be the section modulus of the first sensitive beam 7-1, A be the cross-sectional area of ​​the first sensitive beam 7-1, E be the elastic modulus of the first sensitive beam 7-1, and a be the tangential strain of the first sensitive beam 7-1 under centripetal force. n a is the normal acceleration experienced by the first sensor 2-1. τ This refers to the tangential acceleration experienced by the first sensor 2-1;

[0020] Voltage signal output from the first Wheatstone bridge 6-1 Voltage signal output from the second Wheatstone bridge 6-2 Where K is the sensitivity coefficient of the first sensor;

[0021] Then the included angle can be obtained. Similarly, we can obtain

[0022]

[0023]

[0024] From geometric relationships, we know that:

[0025]

[0026] x = r1sin(-θ1)

[0027]

[0028] y = r²sin(-θ²)

[0029]

[0030] x = r3sin(-θ3)

[0031] Solving the above equations simultaneously, we get:

[0032]

[0033]

[0034]

[0035] Where D is the distance between the centers of the first sensor 2-1 and the third sensor 2-3; where θ1 is calculated from the first sensor 2-1 and the first Wheatstone bridge 6-1 and the second Wheatstone bridge 6-2 connected to it; θ2 is calculated from the second sensor 2-2 and the third Wheatstone bridge 6-3 and the fourth Wheatstone bridge 6-4 connected to it; and θ2 is calculated from the third sensor 2-3 and the fifth Wheatstone bridge 6-5 and the sixth Wheatstone bridge 6-6 connected to it. This system of equations is an overdetermined system of equations about (x, y). Solving any two equations simultaneously will yield the coordinates (x, y) of the eccentric rotation center. Therefore, a weighted simultaneous equation method is used to solve this system of equations.

[0036] Simultaneous equations

[0037]

[0038]

[0039] Calculated

[0040]

[0041]

[0042] Simultaneous equations

[0043]

[0044]

[0045] Calculated

[0046]

[0047]

[0048] Take the average of the results of the two simultaneous equations:

[0049]

[0050]

[0051] If one sensor fails during actual use, its output signal will no longer be used in the eccentricity calculation. If the third sensor fails, the calculated coordinates (x, y) of the eccentricity rotation center will be:

[0052]

[0053]

[0054] This determined the position of the eccentric rotation center, i.e., the eccentricity was measured.

[0055] The angular velocity calculation method of the angular velocity sensor is as follows:

[0056] Using the angles θ1 between r1 and the y-axis, θ2 between r2 and the x-axis, and θ3 between r3 and the y-axis, and then calculating the coordinates (x, y) of the eccentric rotation center, according to the equation:

[0057] x = r1sin(-θ1)

[0058] y = r²sin(-θ²)

[0059] x = r3sin(-θ3)

[0060] Solving for r1, r2, and r3, further, according to the equation:

[0061]

[0062]

[0063] The rotational angular velocity ω can then be obtained by solving:

[0064]

[0065] When calculating r1, r2, and r3, the coordinates (x, y) of the eccentric rotation center need to be substituted. These (x, y) values ​​are obtained through a weighted calculation using three sensors. Therefore, the two terms in the denominator of the final calculated rotational angular velocity ω are the result of a weighted average. If one sensor fails during actual use, its output signal is no longer used in the angular velocity calculation. If the third sensor fails, the expression for the calculated rotational angular velocity should be:

[0066]

[0067] Compared with the prior art, the present invention has the following advantages:

[0068] 1. This invention is a screw speed and angular velocity sensor for screw pump oil pumping units, which can detect the screw angular velocity in real time and realize data interconnection.

[0069] 2. Compared with traditional angular velocity sensors, the sensor of this invention can measure the position of the eccentric rotation center at the same time as measuring the angular velocity, thereby guiding technicians to change the installation position to eliminate the influence of the eccentricity.

[0070] 3. The angular velocity sensor with eccentricity elimination described in this invention uses a weighted calculation method when calculating the eccentricity. In the harsh working environment of the screw pump oil extraction unit described in this invention, the sensor is easily affected by external environmental factors during actual operation, which may cause it to malfunction or produce errors. The angular velocity sensor with eccentricity elimination described in this invention can use a weighted averaging method to eliminate errors as much as possible. At the same time, even if one sensor fails, the remaining sensors can still measure angular velocity and eccentricity, which greatly extends the service life of the sensor.

[0071] 4. The sensor described in this invention has a simple structure and is easy to manufacture and install. Attached Figure Description

[0072] Figure 1 This is an external view of the angular velocity sensor of the present invention.

[0073] Figure 2 This is a front perspective view of the angular velocity sensor structure of the present invention.

[0074] Figure 3 This is a perspective view of the angular velocity sensor structure of the present invention.

[0075] Figure 4 This is a schematic diagram of the strain gauge attachment for the first sensor 2-1 of the present invention.

[0076] Figure 5 This is a schematic diagram of the first Wheatstone bridge 6-1 connected to the first sensor 2-1 of the present invention for measuring centripetal acceleration.

[0077] Figure 6 This is a schematic diagram of the second Wheatstone bridge 6-2 connected to the sensor 2-1 of the present invention for measuring eccentric acceleration.

[0078] Figure 7 This is a schematic diagram of the strain gauge attachment for the second sensor 2-2 of the present invention.

[0079] Figure 8 This is a schematic diagram of the third Wheatstone bridge 6-3 connected to the second sensor 2-2 of the present invention for measuring centripetal acceleration.

[0080] Figure 9 This is a schematic diagram of the fourth Wheatstone bridge 6-4 connected to the second sensor 2-2 of the present invention for measuring eccentric acceleration.

[0081] Figure 10 This is a schematic diagram of the bonding of strain gauges 2-3, the third sensor of the present invention.

[0082] Figure 11 This is a schematic diagram of the fifth Wheatstone bridge 6-5 connected to the third sensor 2-3 of the present invention for measuring centripetal acceleration.

[0083] Figure 12 This is a schematic diagram of the sixth Wheatstone bridge 6-6 connected to the third sensor 2-3 of the present invention for measuring eccentric acceleration.

[0084] Figure 13 This is a schematic diagram illustrating the calculation of the (x, y) coordinates of the eccentric rotation center by the angular velocity sensor of the present invention. Detailed Implementation

[0085] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0086] like Figure 1 , Figure 2 and Figure 3As shown, an angular velocity sensor with eccentricity elimination for a screw pump oil extraction unit comprises: an open base 1, three inertial sensors: a first sensor 2-1, a second sensor 2-2, and a third sensor 2-3, three sensor sealing covers for sealing the three inertial sensors: a first sensor sealing cover 4-1, a second sensor sealing cover 4-2, and a third sensor sealing cover 4-3, and three fixing screws 5. The open base 1 has a U-shaped opening and two concentric arcs, with the center of the two concentric arcs set as the rotation center. The first sensor 2-1, the second sensor 2-2, and the third sensor 2-3 are all inertial sensors, symmetrically installed at positions 90°, 180°, and 270° from the opening direction of the open base 1, respectively. The first sensor 2-1, the second sensor 2-2, and the third sensor 2-3 are all equidistant from the rotation center. Set the sensor's sensitive direction to face the center of rotation.

[0087] like Figure 4 As shown, the first sensor 2-1 includes a first sensitive beam 7-1 and a first strain gauge 3-1, a second strain gauge 3-2, a third strain gauge 3-3, and a fourth strain gauge 3-4 arranged on the first sensitive beam 7-1. The first strain gauge 3-1 and the fourth strain gauge 3-4 are mounted on the side closer to the rotation center, while the second strain gauge 3-2 and the third strain gauge 3-3 are mounted on the side farther from the rotation center. The first strain gauge 3-1 and the second strain gauge 3-2 are mounted at the same end of the sensitive beam 7-1, and the fourth strain gauge 3-4 and the third strain gauge 3-3 are mounted at the same end of the first sensitive beam 7-1. Figure 5 As shown, the first strain gauge 3-1, the second strain gauge 3-2, the fourth strain gauge 3-4, and the third strain gauge 3-3 are connected clockwise in sequence to form the first Wheatstone bridge 6-1. Figure 6 As shown, the third strain gauge 3-3, the second strain gauge 3-2, the fourth strain gauge 3-4, and the first strain gauge 3-1 are connected clockwise in sequence to form the second Wheatstone bridge 6-2.

[0088] like Figure 7 As shown, the second sensor 2-2 includes a second sensitive beam 7-2 and a fifth strain gauge 3-5, a sixth strain gauge 3-6, a seventh strain gauge 3-7, and an eighth strain gauge 3-8 arranged on the second sensitive beam 7-2. The fifth strain gauge 3-5 and the eighth strain gauge 3-8 are mounted on the side closer to the rotation center, while the sixth strain gauge 3-6 and the seventh strain gauge 3-7 are mounted on the side farther from the rotation center. The fifth strain gauge 3-5 and the sixth strain gauge 3-6 are mounted at the same end of the second sensitive beam 7-2, and the 3-7 and the eighth strain gauge 3-8 are mounted at the same end of the second sensitive beam 7-2. Figure 8As shown, the fifth strain gauge 3-5, the sixth strain gauge 3-6, the eighth strain gauge 3-8, and the seventh strain gauge 3-7 are connected clockwise in sequence to form the third Wheatstone bridge 6-3. Figure 9 As shown, the seventh strain gauge 3-7, the sixth strain gauge 3-6, the eighth strain gauge 3-8, and the fifth strain gauge 3-5 are connected clockwise in sequence to form the fourth Wheatstone bridge 6-4.

[0089] like Figure 10 As shown, the third sensor 2-3 includes a third sensitive beam 7-3 and a ninth strain gauge 3-9, a tenth strain gauge 3-10, an eleventh strain gauge 3-11, and a twelfth strain gauge 3-12 arranged on the third sensitive beam 7-3. The ninth strain gauge 3-9 and the twelfth strain gauge 3-12 are mounted on the side closer to the rotation center, while the tenth strain gauge 3-10 and the eleventh strain gauge 3-11 are mounted on the side farther from the rotation center. The ninth strain gauge 3-9 and the tenth strain gauge 3-10 are mounted at the same end of the sensitive beam 7-3, and the eleventh strain gauge 3-11 and the twelfth strain gauge 3-12 are mounted at the same end of the sensitive beam 7-3. Figure 11 As shown, the ninth strain gauge 3-9, the tenth strain gauge 3-10, the twelfth strain gauge 3-12, and the eleventh strain gauge 3-11 are connected clockwise in sequence to form the fifth Wheatstone bridge 6-5. Figure 12 As shown, the eleventh strain gauge 3-11, the tenth strain gauge 3-10, the twelfth strain gauge 3-12, and the ninth strain gauge 3-9 are connected clockwise in sequence to form the fourth Wheatstone bridge 6-4.

[0090] The angular velocity sensor uses three inertial sensors arranged in a specific orientation and installed on the screw of the screw pump oil pumping unit. The specific installation method is as follows: first, place the packaged angular velocity sensor on the screw rotating platform of the screw pump oil pumping unit, pass the screw through the U-shaped groove in the middle of the open base 1, and then use three screws 5 to pass through the bottom of the screw rotating platform to tighten and fix the open base 1 to the screw rotating platform.

[0091] If improper installation causes the actual rotation center to deviate from the design rotation center, the deformation voltage caused by centrifugal force and eccentric force is measured by the Wheatstone bridge formed by the strain gauges on the sensitive beam. The effect of eccentricity is eliminated by calculation, and the angular velocity of the rotating screw under test is calculated. At the same time, the eccentricity between the actual rotation center and the design rotation center is measured.

[0092] like Figure 13As shown, specifically, consider the following eccentric rotation: Taking the center of rotation, i.e., the center of the open base 1, as the origin, the coordinates of the eccentric rotation center are (x, y). The angular velocity of the open base 1 is ω. The distance from the first sensor 2-1 to the eccentric rotation center is r1, and the angle between r1 and the y-axis is θ1. The distance from the second sensor 2-2 to the eccentric rotation center is r2, and the angle between r2 and the x-axis is θ2. The distance from the third sensor 2-3 to the eccentric rotation center is r3, and the angle between r3 and the y-axis is θ3. Taking the first sensor 2-1 as an example, the first sensor 2-1 is subjected to a centripetal acceleration a. 1n With eccentric acceleration a 1τ Together, they work together, including:

[0093] a 1n =ω 2 r1cos(θ1)

[0094] a 1τ =ω 2 r1sin(θ1)

[0095] For the first sensor 2-1, four strain gauges 3-1, 3-2, 3-3, and 3-4 are attached to the root of its first sensing beam 7-1. The first sensor 2-1 is connected to the first Wheatstone bridge 6-1 and the second Wheatstone bridge 6-2. According to mechanics of materials, the following can be known:

[0096] The strain generated by the first strain gauge 3-1 is

[0097] The strain generated by the second strain gauge 3-2 is

[0098] The strain generated by the third strain gauge 3-3 is

[0099] The strain generated by the fourth strain gauge 3-4 is

[0100] Where ε n ε represents the axial strain of the first sensitive beam 7-1 under centripetal force. τ Let be the tangential strain of the first sensitive beam 7-1 under centripetal force, m be the equivalent mass of the first sensitive beam 7-1, L be the length of the first sensitive beam 7-1, W be the section modulus of the first sensitive beam 7-1, A be the cross-sectional area of ​​the first sensitive beam 7-1, E be the elastic modulus of the first sensitive beam 7-1, and a be the tangential strain of the first sensitive beam 7-1 under centripetal force. n a is the normal acceleration experienced by the first sensor 2-1. τ This refers to the tangential acceleration experienced by the first sensor 2-1;

[0101] The voltage signal output from the 6-1 section of the 7-1 Wheatstone bridge Voltage signal output from the second Wheatstone bridge 6-2 Where K is the sensitivity coefficient of the first sensor;

[0102] Then the included angle can be obtained. Similarly, we can also obtain

[0103]

[0104]

[0105] Next step, according to Figure 13 From geometric relationships, we know that:

[0106]

[0107] x = r1sin(-θ1)

[0108]

[0109] y = r²sin(-θ²)

[0110]

[0111] x = r3sin(-θ3)

[0112] Solving the above equations simultaneously, we can obtain:

[0113]

[0114]

[0115]

[0116] The coordinates (x, y) of the eccentric rotation center can be obtained by solving a weighted simultaneous equation:

[0117]

[0118]

[0119] Furthermore, we can use the equation:

[0120] x = r1sin(-θ1)

[0121] y = r²sin(-θ²)

[0122] x = r3sin(-θ3)

[0123] Solving for r1, r2, and r3 yields:

[0124]

[0125]

[0126]

[0127] Furthermore, according to the equation:

[0128]

[0129] The rotational angular velocity ω can then be calculated.

[0130]

Claims

1. An angular velocity sensor for use in screw pump oil extraction units with eliminateable eccentricity, characterized in that: The eccentricity-eliminating angular velocity sensor includes an open base (1), three inertial sensors mounted on the open base (1), and sensor sealing covers sealing the three inertial sensors. The three inertial sensors are a first sensor (2-1), a second sensor (2-2), and a third sensor (2-3). The open base (1) has a U-shaped opening and two concentric arcs, with the center of the two concentric arcs set as the rotation center. The first sensor (2-1), the second sensor (2-2), and the third sensor (2-3) are all inertial sensors, symmetrically installed at positions 90°, 180°, and 270° from the opening direction of the open base (1), respectively. The first sensor (2-1), the second sensor (2-2), and the third sensor (2-3) are all equidistant from the rotation center. The sensor's sensitive direction is set towards the rotation center; the first sensor (2-1) includes a first sensitive beam (7-1) and a first strain gauge (3-1), a second strain gauge (3-2), a third strain gauge (3-3), and a fourth strain gauge (3-4) arranged on the first sensitive beam (7-1). The first strain gauge (3-1) and the fourth strain gauge (3-4) are mounted closer to the rotation center, the second strain gauge (3-2) and the third strain gauge (3-3) are mounted away from the rotation center, the first strain gauge (3-1) and the third strain gauge (3-3) are mounted at the same end of the first sensitive beam (7-1), and the fourth strain gauge (3-4) and the third strain gauge (3-3) are mounted at the same end of the first sensitive beam (7-1). The first strain gauge... The strain gauge (3-1), the second strain gauge (3-2), the fourth strain gauge (3-4), and the third strain gauge (3-3) are connected clockwise in sequence to form the first Wheatstone bridge (6-1). The third strain gauge (3-3), the second strain gauge (3-2), the fourth strain gauge (3-4), and the first strain gauge (3-1) are connected clockwise in sequence to form the second Wheatstone bridge (6-2). The structure of the second sensor (2-2) and the way in which the third Wheatstone bridge (6-3) and the fourth Wheatstone bridge (6-4) are formed are the same as those of the first sensor (2-1). The structure of the third sensor (2-3) and the way in which the fifth Wheatstone bridge (6-5) and the sixth Wheatstone bridge (6-6) are formed are also the same as those of the first sensor (2-1). The angular velocity sensor is installed on the screw of the screw pump oil pump. The specific installation method is as follows: first, place the angular velocity sensor on the screw rotating platform of the screw pump oil pump, pass the screw through the U-shaped opening in the middle of the open base (1), and then use screws to tighten and fix the open base (1) to the screw rotating platform. If improper installation causes the actual rotation center to deviate from the design rotation center, the deformation voltage caused by centrifugal force and eccentric force is measured by the Wheatstone bridge formed by the strain gauges on the sensitive beam. The effect of eccentricity is eliminated by calculation, and the angular velocity of the rotating screw under test is calculated. At the same time, the eccentricity between the actual rotation center and the design rotation center is measured.

2. The angular velocity sensor with eliminateable eccentricity for a screw pump oil extraction unit according to claim 1, characterized in that: The open base (1) is made of cast iron.

3. The angular velocity sensor with eliminateable eccentricity for a screw pump oil extraction unit according to claim 1, characterized in that: The method for measuring eccentricity using the angular velocity sensor is as follows: Consider the following eccentric rotation: with the set rotation center as the origin, the coordinates of the eccentric rotation center are (x, y), and the rotational angular velocity of the open base (1) is ω. The distance from the first sensor (2-1) to the eccentric rotation center is r1, and the angle between r1 and the y-axis is θ1. The distance from the second sensor (2-2) to the eccentric rotation center is r2, and the angle between r2 and the x-axis is θ2. The distance from the third sensor (2-3) to the eccentric rotation center is r3, and the angle between r3 and the y-axis is θ3. Consider the force situation of the first sensor (2-1): the first sensor (2-1) is subjected to a centripetal acceleration a. n With eccentric acceleration a τ Together, they work together, including: a n =ω 2 r1cos(θ1) a τ =ω 2 r1sin(θ1) For the first sensor (2-1), the four strain gauges attached to the root of its first sensing beam (7-1) are connected to form a first Wheatstone bridge (6-1) and a second Wheatstone bridge (6-2), respectively. According to mechanics of materials: The strain generated by the first strain gauge (3-1) is The strain generated by the second strain gauge (3-2) is The strain generated by the third strain gauge (3-3) is The strain generated by the fourth strain gauge (3-4) is Where ε n ε represents the axial strain of the first sensitive beam (7-1) under centripetal force. τ Let be the tangential strain of the first sensitive beam (7-1) under centripetal force, m be the equivalent mass of the first sensitive beam (7-1), L be the length of the first sensitive beam (7-1), W be the section modulus of the first sensitive beam (7-1), A be the cross-sectional area of ​​the first sensitive beam (7-1), E be the elastic modulus of the first sensitive beam (7-1), and a be the tangential strain of the first sensitive beam (7-1). n Let a be the normal acceleration experienced by the first sensor (2-1). τ The tangential acceleration experienced by the first sensor (2-1); Voltage signal output from the first Wheatstone bridge (6-1) Voltage signal output from the second Wheatstone bridge (6-2) Where K is the sensitivity coefficient of the first sensor; Then the included angle can be obtained. Similarly, we can obtain From geometric relationships, we know that: x = r1sin(-θ1) y = r²sin(-θ²) x = r3sin(-θ3) Combining the above equations, we obtain the following system of equations: Where D is the distance between the centers of the first sensor (2-1) and the third sensor (2-3); θ1 is calculated from the first sensor (2-1) and the first Wheatstone bridge (6-1) and the second Wheatstone bridge (6-2) connected to it; θ2 is calculated from the second sensor (2-2) and the third Wheatstone bridge (6-3) and the fourth Wheatstone bridge (6-4) connected to it; θ3 is calculated from the third sensor (2-3) and the fifth Wheatstone bridge (6-5) and the sixth Wheatstone bridge (6-6) connected to it. This system of equations is an overdetermined system of equations about (x,y). Solving any two equations simultaneously will yield the coordinates (x,y) of the eccentric rotation center. Therefore, a weighted simultaneous equation method is used to solve this system of equations. Simultaneous equations Calculated Simultaneous equations Calculated Take the average of the results of the two simultaneous equations: If one sensor fails during actual use, its output signal will no longer be used in the eccentricity calculation. If the third sensor fails, the calculated coordinates (x, y) of the eccentricity rotation center will be: This determined the position of the eccentric rotation center, i.e., the eccentricity was measured.

4. The angular velocity sensor with eliminateable eccentricity for a screw pump oil extraction unit according to claim 3, characterized in that: The angular velocity calculation method of the angular velocity sensor is as follows: Using the angles θ1 between r1 and the y-axis, θ2 between r2 and the x-axis, and θ3 between r3 and the y-axis, and then calculating the coordinates (x, y) of the eccentric rotation center, according to the equation: x = r1sin(-θ1) y = r²sin(-θ²) x = r3sin(-θ3) Solving for r1, r2, and r3, further, according to the equation: The rotational angular velocity ω can then be obtained by solving: When calculating r1, r2, and r3, the coordinates (x, y) of the eccentric rotation center need to be substituted. Since (x, y) is obtained through weighted calculation using three sensors, the two terms in the denominator of the final calculated rotational angular velocity ω are the result of a weighted average. If one sensor fails during actual use, its output signal is no longer used in the angular velocity calculation. If the third sensor fails, the expression for the calculated rotational angular velocity should be:

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