An accelerometer testing device and testing method

Abstract

This invention discloses an accelerometer testing device and method, belonging to the technical field of electric centrifugal turntables. The accelerometer testing device includes a base and a photoelectric velocity sensing module. A turntable is rotatably connected to the base, and the upper end of the turntable is connected to an optical axis. The optical axis is connected to the main shaft of a power unit via a coupling. The optical axis is fixedly connected to the movable inner ring of a slip ring, and the outer ring of the slip ring is fixedly connected to a slip ring fixing seat. The slip ring fixing seat is fixedly connected to an upper plate. The upper plate is connected to the base via several support columns. The turntable is press-fitted with the inner ring of a bearing fixed on the base via a journal extending from its bottom, and positioned by a shoulder engaging with the end face of the inner ring of the bearing. It features low vibration and high precision.

Description

Technical Field

[0001] This invention belongs to the field of electric centrifugal turntable technology, specifically relating to an acceleration sensor testing device and testing method. Background Technology

[0002] Accelerometers are a type of sensor used to measure the acceleration of an object. Integrating accelerometers can indirectly measure displacement for inertial navigation, and can also measure the acceleration of vibrations and shocks to characterize their intensity. The static characteristics of an accelerometer refer to its response characteristics during static acceleration loading and unloading processes, including sensitivity, hysteresis, and nonlinearity.

[0003] When performing static acceleration loading tests on sensors, a stable centrifugal acceleration value needs to be applied to the accelerometer to obtain reliable test data for sensor performance calibration. Therefore, high requirements are placed on the rotational accuracy of the centrifugal turntable and the vibration and noise suppression of the testing system. Currently, the common practice is to fix the turntable above the drive and transmission components, such as the motor, for direct motor drive. However, due to the large rotational inertia of the turntable and its distance from the fixed base, vibrations caused by installation and manufacturing errors are often amplified, affecting the accuracy of the testing system and potentially leading to safety issues. To improve the stability of such turntables, a large turntable and low rotational speed are often used to achieve high acceleration values. However, this method results in large, bulky, and expensive testing equipment, hindering its application and widespread adoption. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a turntable for testing the static characteristics of high-precision, low-vibration accelerometers. This turntable features a simple structure, reduced vibration and noise, and high accuracy in applied acceleration.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An accelerometer testing device includes a base and a photoelectric speed sensing module. A turntable is rotatably connected to the base, and the upper end of the turntable is connected to an optical axis. The optical axis is connected to the main shaft of a power unit via a coupling. The optical axis is fixedly connected to the movable inner ring of a slip ring, and the outer ring of the slip ring is fixedly connected to a slip ring fixing seat. The slip ring fixing seat is fixedly connected to an upper plate. The upper plate is connected to the base via several support columns. The turntable is press-fitted with the inner ring of a bearing fixed on the base via a journal extending from its bottom, and is positioned by a shoulder engaging with the end face of the inner ring of the bearing.

[0007] Furthermore, the turntable includes a rotating plate, with a boss fixed at the upper end of the rotating plate and a groove on the top of the boss. A stepped shaft is fixedly connected to the lower end of the rotating plate, and the stepped shaft includes a shoulder and a journal. Multiple sets of slots are formed on the rotating plate along the circumferential direction, and each set of slots includes several turntable slots arranged radially.

[0008] Furthermore, the slip ring mounting base is provided with through holes, a first threaded hole and a second threaded hole. The through holes penetrate the entire slip ring mounting base and serve as the moving area of ​​the coupling and the slip ring lead-out area. The first threaded hole is located on the upper part of the slip ring mounting base and is used to connect with the upper plate and the DC motor. The second threaded hole is located on the lower part of the slip ring mounting base and is used to connect with the outer ring of the slip ring.

[0009] Furthermore, the support columns are made of profiles.

[0010] Furthermore, the power unit is mounted on the upper plate.

[0011] Furthermore, it also includes a speed governor for controlling the rotational speed of the power unit.

[0012] Furthermore, the couplings, slip rings, and bearings are all standard parts.

[0013] Furthermore, several feet are installed at the lower end of the base.

[0014] An accelerometer testing method based on the above-mentioned accelerometer testing device includes the following steps:

[0015] S1. Fix the acceleration sensor to be measured on the turntable and connect it to the inner ring of the slip ring through the lead wire;

[0016] S2. Start the power unit to drive the turntable to rotate. Obtain the rotation speed of the turntable through the photoelectric speed sensor module, and obtain the current acceleration value of the turntable based on the rotation speed.

[0017] S3. The output voltage signal of the acceleration sensor under test is derived through the slip ring. The output voltage signal is collected, and the static sensitivity of the sensor is calculated based on the change in acceleration and the change in output voltage. The calculation formula is: S=ΔV / Δa; where S is the static sensitivity of the sensor, ΔV is the change in output voltage, and Δa is the change in acceleration of the turntable.

[0018] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0019] In the device described in this invention, the positioning components such as the turntable base and bearings are located in the lower part of the turntable; the driving and transmission components such as the motor, slip ring, upper plate, coupling, and slip ring fixing parts are all located in the upper part of the turntable. This invention reduces vibration bending moment by separating the driving and positioning components and moving the turntable with a large moment of inertia to the fixed base, thus ensuring low vibration and high precision.

[0020] Furthermore, in this invention, apart from the turntable, upper plate, base, and slip ring fixing parts which require machining, the rest are all made of standard parts, such as standard V DC motors, standard motor speed controllers, standard DC voltage sources, standard bearings, standard couplings, and standard slip rings, which significantly reduces the design difficulty and machining costs.

[0021] Furthermore, the motor and turntable are connected by a coupling to transmit torque, which has high transmission efficiency and can compensate for the relative error caused by the installation of the motor and turntable, thereby improving the operational stability of the equipment.

[0022] The testing method provided by this invention only requires mounting the acceleration sensor under test on a turntable and connecting it with leads, powering it with an external DC power supply, and controlling the rotation speed with a speed controller. Since the turntable is fixed on a bearing, the output voltage of the sensor under test under different accelerations can be measured and the output voltage can be kept stable. The static sensitivity can be measured by calculation using a formula, thus achieving a simple and efficient measurement of the sensor's static sensitivity. Attached Figure Description

[0023] Figure 1 This is a perspective view of the turntable of the present invention;

[0024] Figure 2 yes Figure 1 Another perspective;

[0025] Figure 3a This is a top view of the custom parts turntable;

[0026] Figure 3b This is a bottom view of the custom parts turntable;

[0027] Figure 3c This is a cross-sectional view of the turntable;

[0028] Figure 4 This is a cross-sectional view showing the turntable and the retaining ring connected by bolts.

[0029] Figure 5a Bottom view of slip ring mounting base;

[0030] Figure 5b This is a top view of the slip ring mounting base;

[0031] Figure 5c This is a sectional view of the slip ring fixing seat;

[0032] Figure 6 This is a schematic diagram showing the fit between the turntable and the inner ring of the bearing;

[0033] Figure 7 This is a schematic diagram showing the connection between the outer ring of the slip ring and the slip ring mounting base.

[0034] In the attached diagram: 1. Motor; 2. Upper plate; 3. Profile; 4. Turntable; 5. Base; 6. Coupling; 7. Slip ring fixing seat; 8. Slip ring; 9. Fixing ring; 10. Bearing; 11. Optical shaft; 12. Foot; 401. Turntable slot; 402. Shaft shoulder; 403. Shaft journal. Detailed Implementation

[0035] To make the objectives and technical solutions of this invention clearer and easier to understand, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0036] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] Reference Figure 1 and Figure 2 This invention proposes a high-precision centrifugal turntable, including a base 5, bearing 10, turntable 4, fixed ring 9, optical shaft 11, coupling 6, slip ring 8, slip ring fixing seat 7, upper plate 2, profile 3, foot 12, motor 1, photoelectric speed measurement sensor module, DC power supply and speed controller, etc.

[0038] The base 5 is a rectangular weight, with its upper end connected to the bearing 10, and rubber feet 12 installed at the four corners of its lower end for leveling. The bearing 10 is a high-speed, low-load bearing, mounted on the base 5 via an integrated bearing housing.

[0039] like Figure 6 As shown, the turntable 4 is directly interference-fitted with the inner ring 10-1 of the bearing 10 fixed on the base 5 via the journal 403 extending from the bottom. Positioning is achieved through the shoulder 402 engaging with the end face of the bearing inner ring 10-1. The turntable 4 and the rolling bearing 10 are connected by an interference fit to ensure accurate turntable positioning, thereby improving rotational accuracy. The rolling bearing is bolted to the base via a bearing housing.

[0040] The base 5 is fixedly connected to the lower end of the profile 3, and the upper end of the profile 3 is connected to the upper plate 2 by bolts. The upper plate 2 serves to fix the slip ring 8 and the motor 1.

[0041] like Figure 7 As shown, the outer ring 801 of the slip ring 8 is fixed and connected to the slip ring fixing seat 7 by a thread. The slip ring fixing seat 7 is fixedly connected to the upper plate 2 and is located below the upper plate 2 to fix the slip ring 8. The inner ring of the slip ring 8 is connected to the motor shaft by a mortise screw to achieve synchronous rotation. In addition, the inner ring of the slip ring 8 can also output the signal of the sensor under test fixed on the turntable through the pins on the fixed outer ring.

[0042] Motor 1 is a DC motor with a maximum no-load speed of 5000 rpm, and it is mounted on the upper plate 2 with bolts. The main shaft of the DC motor is connected to the optical shaft 11 via a coupling 6.

[0043] Reference Figure 3a , Figure 3b Figure 3c and Figure 4 The turntable 4 includes a rotating plate 404, with a boss 405 fixed to the upper end of the rotating plate 404. A groove 406 is formed on the top of the boss 405. A stepped shaft is fixedly connected to the lower end of the rotating plate 404. The stepped shaft includes a shoulder 402 and a journal 403. Four sets of slots are formed along the circumferential direction on the rotating plate 404. Each set of slots includes four turntable slots 401 evenly arranged radially.

[0044] Reference Figure 5a , Figure 5b and Figure 5cThe slip ring mounting base 7 has a through hole 701, a first threaded hole 702, and a second threaded hole 703. The through hole 701 extends through the entire slip ring mounting base 7, serving as the moving area of ​​the coupling 6 and the lead-out area of ​​the slip ring 8. The coupling 6 is located inside the through hole 701. There are four first threaded holes 702 located on the upper part of the slip ring mounting base 7, used for connecting it to the upper plate 2 and the DC motor 1. There are two second threaded holes 703 located on the lower surface of the slip ring mounting base 7, used for connecting the outer ring of the slip ring 8 to it.

[0045] By placing positioning components such as the turntable base 5 and bearing 10 in the lower part of the turntable, and by placing driving and transmission components such as the motor 1, slip ring 8, coupling 6, optical shaft 11, upper plate 2 and slip ring fixing seat 7 in the upper part of the turntable, the driving part and the positioning part are separated, and the turntable 4 with a large moment of rotational inertia is moved down to the fixed base 5 to reduce the vibration bending moment, thereby ensuring reduced vibration and improved accuracy.

[0046] Among them, motor 1 is a standard V-type DC motor, speed controller is a standard motor speed controller, DC power supply is a standard DC voltage source, bearing 10 is a standard bearing, coupling 6 is a standard coupling, and slip ring 8 is a standard slip ring, which significantly reduces costs.

[0047] like Figure 1 , Figure 2 As shown, the specific assembly method of the present invention is as follows:

[0048] The bearing 10 is connected to the base 5 with four M12 bolts; four feet 12 for vibration isolation and leveling are installed below the base 5; the movable inner ring 10-1 of the bearing 10 is interference-fitted with the journal 403 below the turntable 4, and the upper surface of the movable inner ring 10-1 of the bearing 10 mates with the end face 403 of the journal of the turntable 4, so that the bearing 10 and the turntable 4 fit tightly together, giving full play to the positioning function of the bearing and improving the rotation accuracy of the turntable; the upper part of the turntable 4 is tightly connected to the fixed ring 9 with two M4 bolts, and the fixed ring 9 is connected by a side-mounted... Bolts clamp the optical shaft 11, allowing the torque of motor 1 to be transmitted to turntable 4. The optical shaft 11 is connected to the movable inner ring of slip ring 8 via grommets, enabling the movable inner ring of slip ring 8 to rotate synchronously with the main shaft of motor 1. The optical shaft 11 is connected to the main shaft of motor 1 via coupling 6 to extend the main shaft of motor 1. When the motor rotates, the power of motor 1 is transmitted from the optical shaft 11 through the movable inner ring of slip ring 8 to the fixed ring 9, which is bolted to turntable 4. The fixed ring 9 drives turntable 4 to rotate on rolling bearings fixed to the base. Turntable 4 is provided with a slot for mounting an acceleration sensor. A DC power supply is connected to a speed controller, which is connected to motor 1. AB glue is used to mount the photoelectric speed measuring module on profile 3, which is powered by a DC power supply to measure the rotational speed of turntable 4. Motor 1 is connected to the upper plate via four M5 bolts mounted on its flange. The upper plate 2 and the base 5 are connected via profile 3.

[0049] An accelerometer testing method based on the accelerometer testing device described above includes the following steps:

[0050] S1. Fix the acceleration sensor to be measured on the turntable and connect it to the inner ring of the slip ring 8 through the lead wire;

[0051] S2. Start the power unit to drive the turntable 4 to rotate. Obtain the rotation speed of the turntable 4 through the photoelectric speed sensor module. Obtain the current acceleration value of the turntable 4 based on the rotation speed of the turntable 4.

[0052] S3. The output voltage signal of the acceleration sensor under test is derived through slip ring 8. The output voltage signal is collected, and the static sensitivity of the sensor is obtained according to the formula S=ΔV / Δa, where S is the static sensitivity of the sensor, ΔV is the change in output voltage, and Δa is the change in acceleration.

[0053] This method only requires mounting the accelerometer under test on the turntable 4 and connecting it with the lead wire, and powering it with an external DC power supply to measure the static sensitivity, thus achieving a simple and efficient measurement of the sensor's static sensitivity.

[0054] The testing method of the present invention is based on the acceleration sensor testing device described above. It not only has the advantages of the testing device described above, but is also simple to operate and easy to implement.

[0055] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. An accelerometer testing device, characterized in that, The system includes a base (5) and a photoelectric speed sensor module. A turntable (4) is rotatably connected to the base (5). The upper end of the turntable (4) is connected to an optical axis (11). The optical axis (11) is connected to the main shaft of the power unit through a coupling (6). The optical axis (11) is fixedly connected to the movable inner ring of a slip ring (8). The outer ring of the slip ring (8) is fixedly connected to a slip ring fixing seat (7). The slip ring fixing seat (7) is fixedly connected to an upper plate (2). The upper plate (2) is connected to the base (5) through several support columns. The turntable (4) is press-fitted with the inner ring (101) of the bearing (10) fixed on the base (5) by the journal (403) extending from the bottom, and is positioned by the shoulder (402) mating with the end face of the inner ring (101) of the bearing.

2. The accelerometer testing device according to claim 1, characterized in that, The turntable (4) includes a rotating plate (404), a boss (405) is fixed on the upper end of the rotating plate (404), a groove (406) is provided on the top of the boss (405), a stepped shaft is fixedly connected to the lower end of the rotating plate (404), the stepped shaft includes a shoulder (402) and a journal (403), and multiple sets of slots are provided on the rotating plate (404) along the circumferential direction, each set of slots including a number of turntable slots (401) arranged radially.

3. The accelerometer testing device according to claim 1, characterized in that, The slip ring fixing seat (7) is provided with a through hole (701), a first threaded hole (702) and a second threaded hole (703). The through hole (701) penetrates the entire slip ring fixing seat (7) and serves as the moving area of ​​the coupling (6) and the lead-out area of ​​the slip ring (8). The first threaded hole (702) is located on the upper part of the slip ring fixing seat (7) and is used to connect with the upper plate (2) and the DC motor (1). The second threaded hole (703) is located on the lower part of the slip ring fixing seat (7) and is used to connect with the outer ring of the slip ring (8).

4. The accelerometer testing device according to claim 1, characterized in that, The support column is a profile (3).

5. The accelerometer testing device according to claim 1, characterized in that, The power unit is mounted on the upper plate (2).

6. An acceleration sensor testing device according to claim 1 or 5, characterized in that, It also includes a speed governor for controlling the speed of the power unit.

7. The accelerometer testing device according to claim 1, characterized in that, The coupling (6), slip ring (8) and bearing (10) are all standard parts.

8. The accelerometer testing device according to claim 1, characterized in that, The lower end of the base (5) is equipped with several feet (12).

9. An acceleration sensor testing method based on an acceleration sensor testing device according to claim 1, characterized in that, Includes the following steps: S1. Fix the acceleration sensor to be tested on the turntable (4) and connect it to the inner ring of the slip ring (8) by means of a lead wire; S2. Start the power unit to drive the turntable (4) to rotate. Obtain the rotation speed of the turntable (4) through the photoelectric speed sensor module. Obtain the current acceleration value of the turntable (4) based on the rotation speed of the turntable (4). S3. The output voltage signal of the acceleration sensor under test is derived through the slip ring (8). The output voltage signal is collected, and the static sensitivity of the sensor is calculated based on the change in acceleration and the change in output voltage. The calculation formula is: S=ΔV / Δa; where S is the static sensitivity of the sensor, ΔV is the change in output voltage, and Δa is the change in acceleration of the turntable.

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