CN116953288A - Accelerometer resolution testing device and method utilizing excitation force of double eccentric motors - Google Patents

Abstract

The invention discloses an accelerometer resolution testing device and method using the excitation force of a double eccentric motor. The stepper motor and accelerometer are installed on the optical platform. The stepper motor shaft is connected with two eccentric blocks. The accelerometer and the terminal computer are connected through a signal acquisition system. The two eccentric modules are symmetrically distributed; the method includes given target acceleration. Change amount, according to the same target acceleration change amount, select multiple sets of target included angles and target included angle increments, and then obtain the average value of the accelerometer output signal amplitude differences corresponding to multiple sets of target included angles and target included angle increments. And compare it with the target acceleration change to determine whether the given target acceleration change reaches the standard, and select the minimum value among the target acceleration changes that meet the standard as the accelerometer resolution. The test of the present invention is carried out on an optical platform, has a simple structure and low cost, can achieve extremely high resolution without resorting to a precision rotating device, and has strong practicability.

Description

Accelerometer resolution testing device and method using double eccentric motor excitation force

Technical field

The invention belongs to the field of accelerometer sensors and relates to an accelerometer resolution testing device and method. In particular, it relates to an accelerometer resolution testing device and method that utilizes the excitation force of a double eccentric motor.

Background technique

The accelerometer is an instrument that measures the linear acceleration of the carrier. It consists of a detection mass (also called a sensitive mass), a support, a potentiometer, a spring, a damper and a housing. It has the characteristics of simple structure and high precision. It is used in inertial navigation systems and geodetic systems. It has a wide range of applications in measurement systems. Resolution is an important indicator of an accelerometer, reflecting the minimum limit of acceleration that the accelerometer can measure. The higher the resolution, the more sensitive the accelerometer is to weak accelerations. Resolution measurement is crucial in the calibration and application of high-precision accelerometers. .

When testing the accelerometer resolution, it is necessary to artificially give the accelerometer a small acceleration input, and then perform signal output sampling and data processing. In order to achieve the measurement of a high-resolution accelerometer, the test method should be at least as long as the accelerometer. The measurement resolution is more than an order of magnitude higher. Generally, the accelerometer resolution is tested by using a mechanical structure device, changing the angle between the sensitive axis and the horizontal plane, or changing the distance between the gravity block and the acceleration. The commonly used test method is to use an optical indexing head to subdivide the gravity field. The minimum scale of the optical indexing head is 0.1″, and the maximum resolution of the accelerometer that can be measured is 0.5ug. The method of uniform rotation modulation can also be used to test the resolution. , the acceleration is installed on a deflectable uniform rotating table, and the gravity acceleration signal is divided into smaller parts. A biaxial turntable can be used to measure a resolution of 0.1ug. The resolution test can also be carried out by using high specific gravity materials to generate gravitational gradients. Four quartz flexible accelerometers are evenly installed at 90° intervals on a biaxial turntable that rotates at a constant angular velocity. The direction of the sensitive axis is the tangential direction of the rotational angular velocity. The moving lead ball produces different sizes of gravity, and the highest resolution can be obtained is 0.01ug. .The resolution test method under 1g excitation uses a precision single-axis rotation device to test the resolution, and uses a reference accelerometer to suppress common mode noise to determine whether the accelerometer under test has a 1×10 ^-8 g capacity. level resolution. The accelerometer resolution test method using a swing device can provide an input acceleration of about 1ug. The high-resolution test method of quartz accelerometers based on a piezoelectric deflection stage is to install a high-precision accelerometer on a piezoelectric deflection table. On the electric deflection stage, the piezoelectric deflection stage is made to perform micro-angle swing at a fixed frequency f on the milliradian scale. It is estimated that the test resolution can reach 1×10 ^-9 g.

Existing high-resolution accelerometer test solutions require the use of precision rotating devices or turntables to provide extremely small acceleration signal inputs. They have high requirements for environmental equipment and high costs. However, general resolution test solutions can only obtain Resolution is limited.

Contents of the invention

In view of the current situation that high-sensitivity accelerometer resolution testing methods require the use of high-precision turntables or rotating devices, which are costly and complicated to install, the purpose of the present invention is to provide an accelerometer resolution testing device that utilizes the excitation force of a double eccentric motor and This method can achieve accurate resolution testing of high-sensitivity accelerometers on a simple device structure.

The technical solutions adopted by the present invention are as follows:

1. An accelerometer resolution testing device using the excitation force of a double eccentric motor:

The device used in the present invention includes an eccentric module, a signal acquisition module, an optical platform, a stepper motor driver and a terminal computer; the optical platform is placed on the ground, two eccentric modules are fixedly installed on the upper surface of the optical platform, and one end of the signal acquisition module Placed on the optical platform, the other end of the signal acquisition module is electrically connected to the terminal computer, and the input end of the eccentric module and the output end of the terminal computer are connected through a stepper motor driver.

The eccentric module includes a stepper motor, a fixed eccentric block and an adjustable eccentric block; the stepper motor is fixedly installed on the upper surface of the optical platform, and the rotating axis of the stepper motor is perpendicular to the upper surface of the optical platform, and the fixed eccentric block and the adjustable eccentric block are The adjustable eccentric blocks are located above the optical platform. The top of the stepper motor shaft is connected to the eccentric position of the fixed eccentric block and the adjustable eccentric block. Both the fixed eccentric block and the adjustable eccentric block make uniform circular motion around the stepper motor shaft. , the pulse input end of the stepper motor and the terminal computer are connected through the stepper motor driver.

The signal acquisition module includes an accelerometer and a signal acquisition system. The accelerometer is placed on an optical platform. The output end of the accelerometer and the terminal computer are connected through the signal acquisition system; the two eccentric modules are symmetrical with the sensitive axis of the accelerometer. The axes are symmetrically distributed, and the connecting lines of the stepper motors in the two eccentric modules are perpendicular to the sensitive axis of the accelerometer.

2. The accelerometer resolution test method using the excitation force of the double eccentric motor includes the following steps:

Step S1) Install the two eccentric modules on the optical platform axially symmetrically with the accelerometer sensitive axis as the symmetry axis, and then set the target acceleration change amount Δa;

Step S2) Obtain the amplitude of the sinusoidal component of the digital electrical signal at the target angle:

Step S2.1) Given the target angle θ, and adjust the angle between the fixed eccentric block and the adjustable eccentric block to the target angle θ;

Step S2.2) At the target angle, control the stepper motor shaft to rotate, then the optical platform and accelerometer sensitive shaft vibrate, and then use the terminal computer to obtain the amplitude of the sinusoidal component of the digital electrical signal at the target angle, and convert the current digital The amplitude of the sinusoidal component of the electrical signal is used as the initial amplitude;

Step S3) Obtain the amplitude of the sinusoidal component of the digital electrical signal under the adjusted angle:

Step S3.1) According to the given target acceleration change Δa and the target included angle θ, determine the adjustment angle θ _c , and then adjust the position of the adjustable eccentric block to make the included angle between the fixed eccentric block and the adjustable eccentric block becomes the adjustment angle θ _c ;

Step S3.2) Under the adjusted included angle θ _c , control the rotation of the stepper motor shaft, then the optical platform and accelerometer sensitive shaft vibrate, use the terminal computer to obtain the amplitude of the sinusoidal component of the digital electrical signal under the adjusted included angle, and store the current The amplitude of the sinusoidal component of the digital electrical signal is used as the adjustment amplitude;

Step S3.3) Process according to the following formula to obtain the amplitude difference at the adjustment angle θ _c :

Amplitude difference = adjustment amplitude – initial amplitude

Step S4) Repeat steps S2) to step S3) multiple times to obtain amplitude differences under different adjustment angles θ _c , and obtain the average of all amplitude differences as the target average amplitude difference corresponding to the target acceleration change Δa;

Step S5) Compare the target acceleration change amount Δa with the corresponding target average amplitude difference to determine whether the given target acceleration change amount is the target acceleration change amount that meets the standard;

Step S6) Repeat steps S1) to step S5) multiple times to obtain several target acceleration changes, and select the minimum value among the target acceleration changes as the resolution of the accelerometer.

In the steps S2.2) and S3.2), the stepper motor shaft is controlled to rotate, then the optical platform and the accelerometer sensitive shaft vibrate, and then the terminal computer is used to obtain the amplitude of the sinusoidal component of the digital electrical signal. The specific steps are:

First, the terminal computer controls the two stepper motor shafts to run in opposite directions and at the same speed through the stepper motor driver. After the stepper motor shaft rotates, it drives the fixed eccentric block and the adjustable eccentric block to move and generate excitation force. The force drives the optical platform to vibrate, and the vibration of the optical platform drives the sensitive axis of the accelerometer to vibrate in a straight line;

Then, the accelerometer converts the acceleration signal under linear reciprocating vibration into an analog electrical signal, and inputs it into the signal acquisition system. The signal acquisition system converts the input analog electrical signal into a digital electrical signal and transmits it to the terminal computer, which is processed by the terminal computer. Separate the signal sinusoidal component in the digital electrical signal, and obtain the amplitude of the corresponding sinusoidal component of the digital electrical signal at the current angle.

In the step S3.1), according to the given target acceleration change Δa and the target included angle θ, the specific steps to determine the adjustment of the included angle θ _c are:

The adjustment angle θ _c is obtained according to the following formula:

θ _c =θ + Δθ

Among them, Δθ is the target angle increment, A is the amplitude of the sinusoidal component of the acceleration signal a at the target angle θ, Δa is the given target acceleration change, and θ is the given target angle.

The specific operations of step S5):

Step S5.1) Compare the target acceleration change Δa obtained in step S4) with the corresponding target average amplitude difference to determine whether the target acceleration change Δa reaches the standard:

If 50%＜target average amplitude difference/target acceleration change＜150%, it means that the target acceleration change is the target acceleration change that meets the standard;

Otherwise, it means that the target acceleration change amount is a target acceleration change amount that does not meet the standard;

The target acceleration change amount Δa is an integer.

The excitation force generated by the stepper motor is calculated according to the following formula:

Among them, m is the sum of the masses of a single fixed eccentric block and a single adjustable eccentric block, r is the distance between the center of mass of the fixed eccentric block and the stepper motor shaft, ω is the angular velocity of the rotating shaft, θ _p is the fixed eccentric block and the adjustable eccentric block. Adjust the actual angle between the eccentric blocks.

Under the target angle θ, the acceleration signal a of the accelerometer's sensitive axis undergoing linear reciprocating vibration is processed according to the following formula:

Among them, M is the total mass of the optical table, m is the sum of the masses of a single fixed eccentric block and a single adjustable eccentric block, r is the distance between the center of mass of the fixed eccentric block and the stepper motor shaft, ω is the rotation angular velocity of the shaft, θ is the target angle, t is the rotation time of the rotating shaft, is the angle between the angular bisector of the fixed eccentric block and the adjustable eccentric block and the sensitive axis of the accelerometer, and eta is the horizontal vibration isolation efficiency of the optical platform at the frequency of the sinusoidal component of the acceleration signal of linear reciprocating vibration.

The inventive principle of the present invention is as follows:

The present invention uses a stepper motor to control the reciprocating vibration of an optical platform. The rotating shaft of the stepper motor is perpendicular to the optical platform. The rotation of the rotating shaft drives the eccentric block to generate centrifugal force, which reacts on the stepper motor fixed with the optical platform, which is the excitation force. The magnitude of the exciting force is:

Among them, m is the sum of the masses of a single fixed eccentric block and a single adjustable eccentric block, r is the distance between the center of mass of the eccentric block and the stepper motor shaft, ω is the angular velocity of the rotating shaft, θ _p is the fixed eccentric block and the adjustable eccentric block. The actual angle between the eccentric blocks.

The fixed motor shaft is loaded with a fixed eccentric block and an adjustable eccentric block of the same specifications. By changing the fixed angle of the adjustable eccentric block, the angle θ _p between the two eccentric blocks is changed, thereby changing the size of the resultant eccentric distance and adjusting the excitation. force size.

The rotating shaft of a single stepper motor is installed vertically on the optical platform. Under the action of the excitation force, the optical platform is driven to produce circular motion. When two stepper motors of the same model run in opposite directions and at the same speed, the motion generated by the optical platform is linear reciprocation. Vibration, the vibration generated by the optical platform drives the sensitive axis of the accelerometer to vibrate in a straight line, and the acceleration signal a of the accelerometer vibrating in a straight line can be written as:

Among them, M is the total mass of the optical table, m is the sum of the masses of a single fixed eccentric block and a single adjustable eccentric block, r is the distance between the center of mass of the fixed eccentric block and the stepper motor shaft, ω is the rotation angular velocity of the shaft, θ _p is the actual angle between the fixed eccentric block and the adjustable eccentric block, t is the rotation time of the rotating shaft, is the angle between the angular bisector of the fixed eccentric block and the adjustable eccentric block and the sensitive axis of the accelerometer, generally 0°, eta is the horizontal vibration of the optical platform at the frequency f of the sinusoidal component of the acceleration signal of linear reciprocating vibration Vibration isolation efficiency.

For example, in the NAP series air-floating vibration isolation optical platform, the optical platform model NAP15-10 weighs 180kg. When the horizontal vibration frequency is 5Hz, the vibration isolation efficiency is 88~94%, and when the vibration frequency is 10Hz, the vibration isolation efficiency is 92%~ 98%. Select an eccentric block with a total mass of 0.1kg and a maximum combined eccentricity of 0.05m in a single group of eccentric modules to be loaded on the stepper motor. The target angle θ between the eccentric blocks is 0°, and the stepper motor speed is adjusted. is 600r/min, and the reciprocating frequency of the optical platform is 10Hz. At this time, the vibration isolation efficiency in the horizontal direction of the optical platform is 95%. According to the formula, the acceleration signal amplitude at this time is 1.1mg.

On this basis, the angle between the two eccentric blocks is changed, thereby changing the size of the resultant eccentricity, adjusting the size of the excitation force, and changing the amplitude of the acceleration. According to the given target acceleration change, select multiple sets of acceleration signal sinusoidal component amplitudes and target included angles, determine the target included angle increment and adjustment included angle, and obtain the corresponding differences between multiple sets of target included angles and adjusted included angles under the target acceleration change. The average value of the output amplitude difference is compared with the ideal output difference, that is, the target acceleration change. Since the output acceleration signal is a sinusoidal signal, it is necessary to perform data processing on the output sinusoidal signal and average multiple acceleration peaks to find its amplitude.

The relationship between the amplitude of the sinusoidal component of the acceleration signal, the target acceleration change, the target included angle, and the target included angle increment satisfy the following relationship:

Among them, Δθ is the target angle increment, A is the amplitude of the sinusoidal component of the acceleration signal at the target angle θ, Δa is the given target acceleration change, and θ is the given target angle. When the target angle θ is 0, the amplitude of the sinusoidal component of the acceleration signal is 1.1mg. If the target angle is 0° and the target acceleration change is 4.2ug, then the target angle increment is 10°; if the target acceleration change is 1.05ug , then select the target angle increment to be 5°. If you choose an optical table with a larger table weight, you can further narrow the selection of target acceleration changes. If higher-precision control of the target angle is improved on this basis, more precise accelerometer resolution testing can be achieved.

The stepper motor provides power for the entire test device. The stepper motor installed on the optical platform is loaded with a fixed eccentric block and an adjustable eccentric block with the same specifications. The eccentric block rotates to generate an exciting force. The stepper motor shaft is installed vertically on the optical platform. on the platform, causing the optical platform to produce weak vibrations in the horizontal direction; two stepper motors of the same model are installed in the same way and run in opposite directions and at the same speed, causing the optical platform to produce linear reciprocating vibrations with adjustable amplitude in the horizontal direction. The accelerometer makes linear reciprocating motion in the direction of the sensitive axis along with the optical platform. Select the target angle between the eccentric blocks and the target angle increment according to the target acceleration change, adjust the excitation force to change the amplitude of the accelerometer input sinusoidal signal, and obtain different output data of the accelerometer. According to the actual output amplitude difference and The ratio of the ideal output difference under the target acceleration change is used to determine whether the resolution of the accelerometer meets the standard.

The beneficial effects of the present invention are:

1. The present invention provides a resolution testing method for accelerometers. It uses an eccentric motor and an optical platform to implement a simple and reliable measurement device. It can achieve the resolution of a high-sensitivity accelerometer without resorting to an expensive and complex precision turntable. Test, and use the method of measuring amplitude to achieve repeated high-precision tests, providing a criterion for carefully measuring the performance and application range of the accelerometer.

2. The test of the present invention is carried out on an optical platform, with simple structure and low cost. It can achieve extremely high resolution of less than 1ug without resorting to precision rotating devices, and has strong practicability.

Description of the drawings

Figure 1 is an overall installation diagram of the device of the present invention;

Figure 2 is a test principle block diagram of the method of the present invention.

In the picture: 1. Stepper motor; 2. Optical platform; 3. Fixed eccentric block; 4. Adjustable eccentric block; 5. Stepper motor driver; 6. Accelerometer; 7. Signal acquisition system; 8. Terminal computer.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and examples:

As shown in Figure 1, the device in the specific implementation includes an eccentric module, a signal acquisition module, an optical platform 2, a stepper motor driver 5 and a terminal computer 8; the optical platform 2 is placed on the ground, and the two eccentric modules are fixedly installed on the optical platform 2, one end of the signal acquisition module is placed on the optical platform 2, the other end of the signal acquisition module is electrically connected to the terminal computer 8, and the input end of the eccentric module and the output end of the terminal computer 8 are connected through a stepper motor. Drive 5 is connected.

The stepper motor driver 5 adopts a digital stepper motor driver;

The eccentric module includes a stepper motor 1, a fixed eccentric block 3 and an adjustable eccentric block 4; the stepper motor 1 is fixedly installed on the upper surface of the optical platform 2, and the rotating axis of the stepper motor 1 is perpendicular to the upper surface of the optical platform 2 and fixed. The eccentric block 3 and the adjustable eccentric block 4 are both located above the optical platform 2. The top of the rotating shaft of the stepper motor 1 is connected to the eccentric positions of the fixed eccentric block 3 and the adjustable eccentric block 4 from bottom to top. The stepper motor 1 The fixed eccentric block 3 and the adjustable eccentric block 4 are driven to make uniform circular motion around the rotating shaft of the stepper motor 1. The pulse input end of the stepper motor 1 and the terminal computer 8 are connected through the stepper motor driver 5.

The fixed eccentric block 3 is fixedly connected to the rotating shaft of the stepper motor 1, and the adjustable eccentric block 4 is rotatably connected to the rotating shaft of the stepper motor 1, so that the fixed eccentric block 3 and the adjustable eccentric block 4 are connected to each other. The angle between them can be changed arbitrarily.

The signal acquisition module includes an accelerometer 6 and a signal acquisition system 7. The accelerometer 6 is placed on the optical platform 2, and the output end of the accelerometer 6 and the terminal computer 8 are connected through the signal acquisition system 7;

The two eccentric modules are symmetrically distributed with the sensitive axis of the accelerometer 6 as the symmetrical axis. The connecting line of the stepper motor 1 in the two eccentric modules is perpendicular to the sensitive axis of the accelerometer 6.

Stepper motor 1 provides power for the entire test device. Stepper motor 1 installed on optical platform 2 is loaded with fixed eccentric block 3 and adjustable eccentric block 4 with the same specifications. The rotation of eccentric blocks 3 and 4 generates exciting force, so that The optical platform 2 generates weak vibrations in the horizontal direction; the stepper motor 1 is used to make the optical platform 2 vibrate in a horizontal straight line, and only the acceleration input along the sensitive axis of the accelerometer 6 is tested. The connection line of the stepper motor 1 in the two eccentric modules is perpendicular to the sensitive axis of the accelerometer 6, causing the sensitive axis of the accelerometer 6 to vibrate in a straight line along its own axis.

As shown in Figures 1 and 2, in the specific implementation, the stepper motor 1 is installed on the optical platform 2, the fixed eccentric block 3 and the adjustable eccentric block 4 are fixed on the stepper motor 1, and the stepper motor 1 rotates to make the fixed eccentric The rotation of block 3 and the adjustable eccentric block 4 generates centrifugal force, which reacts on the stepper motor 1. The vibration of the stepper motor 1 in turn drives the optical platform 2 to vibrate. Two identical eccentric motors make the optical platform 2 vibrate in a linear direction. Using digital The stepper motor driver 5 controls two stepper motors 1 to run in opposite directions at the same speed. The accelerometer 6 is fixed on the optical platform and receives the acceleration signal of the optical platform 2. The signal acquisition system 7 samples the acceleration and outputs an electrical signal, which is processed in the terminal computer 8 signal processing and evaluation.

The method of the present invention includes the following steps:

Step S1) Install the two eccentric modules on the optical platform 2 axially symmetrically with the sensitive axis of the accelerometer 6 as the symmetry axis, then give the initial target acceleration change Δa, and proceed to step S2);

Step S2) Obtain the amplitude of the sinusoidal component of the digital electrical signal at the target angle:

Step S2.1) Given the target included angle θ, and adjust the included angle between the fixed eccentric block 3 and the adjustable eccentric block 4 to the target included angle θ;

Step S2.2) At the target included angle, control the rotation axis of the stepper motor 1 to rotate, then the optical platform 2 and the accelerometer 6 sensitive axes vibrate, and then use the terminal computer 8 to obtain the amplitude of the sinusoidal component of the digital electrical signal at the target included angle, And take the amplitude of the sinusoidal component of the current digital electrical signal as the initial amplitude;

Step S3) Obtain the amplitude of the sinusoidal component of the digital electrical signal under the adjusted included angle;

Step S3.1) According to the given target acceleration change Δa and the target included angle θ, determine the adjustment angle θ _c , and then adjust the position of the adjustable eccentric block 4 so that the gap between the fixed eccentric block 3 and the adjustable eccentric block 4 The included angle becomes the adjusted included angle θ _c ;

Step S3.2) Under the adjusted included angle θ _c , control the rotation of the stepper motor 1 shaft, then the optical platform 2 and the accelerometer 6 sensitive axes vibrate, and use the terminal computer 8 to obtain the amplitude of the sinusoidal component of the digital electrical signal under the adjusted included angle. , and use the amplitude of the sinusoidal component of the current digital electrical signal as the adjustment amplitude;

Step S3.3) Process according to the following formula to obtain the amplitude difference corresponding to the adjustment angle θ _c :

Amplitude difference = adjustment amplitude – initial amplitude

Step S4) Repeat steps S2) to step S3) multiple times to obtain the amplitude difference under different adjustment angles θ _c when the target acceleration change Δa is the same, and obtain the average of all amplitude differences as the target acceleration change Δa The corresponding target average amplitude difference;

Step S5) Compare the target acceleration change Δa with the corresponding target average amplitude difference to determine whether the given target acceleration change reaches the standard;

Step S6) Reset the target acceleration change amount, and then repeat steps S2) to step S5) multiple times according to different target acceleration change amounts Δa to obtain several target acceleration change amounts that meet the target, and select the smallest of the target acceleration change amounts that meet the target. The value serves as the resolution of the accelerometer 6.

In step S2.2) and step S3.2), the stepper motor 1 is controlled to rotate at different angles, and then the optical platform 2 and the accelerometer 6 are sensitive to axis vibration, and then the terminal computer 8 is used to obtain digital electrical signals at different angles. The specific steps for determining the amplitude of the sinusoidal component of a signal are:

First, the terminal computer 8 controls the rotating shafts of the two stepper motors 1 to run in opposite directions and at the same speed through the stepper motor driver 5. After the rotating shaft of the stepper motor 1 rotates, it drives the fixed eccentric block 3 and the adjustable eccentric block 4 to move and generate The exciting force drives the optical platform 2 to vibrate. After the optical platform 2 vibrates, it drives the sensitive axis of the accelerometer 6 to vibrate in a straight line;

At the same time, the speed of the stepper motor 1 is adjusted so that the frequency of the sinusoidal component of the acceleration signal of the linear reciprocating vibration of the accelerometer 6 is f;

Then, the accelerometer 6 converts the acceleration signal under linear reciprocating vibration into an analog electrical signal, and inputs it into the signal acquisition system 7. The signal acquisition system 7 converts the input analog electrical signal into a digital electrical signal and transmits it to the terminal computer 8. The terminal computer 8 is used to process and separate the sinusoidal component of the signal with frequency f in the digital electrical signal, and obtain the amplitude of the corresponding sinusoidal component of the digital electrical signal when the frequency of the sinusoidal component of the acceleration signal is f at the current angle.

In step S3.1), according to the given target acceleration change Δa and the target included angle θ, the specific steps to determine the adjustment of the included angle θ _c are:

The adjustment angle θ _c is obtained according to the following formula:

θ _c =θ + Δθ

Among them, Δθ is the target angle increment, a is the amplitude of the sinusoidal component of the acceleration signal a when the sensitive axis of the accelerometer (6) vibrates in a straight line at the target angle θ, Δa is the given target acceleration change, and θ is the given fixed target angle.

Specific operations of step S5):

Compare the target acceleration change Δa obtained in step S4) with the corresponding target average amplitude difference to determine whether the target acceleration change Δa reaches the standard:

If 50%＜corresponding target average amplitude difference/target acceleration change＜150%, it means that the target acceleration change reaches the standard;

Otherwise, it means that the target acceleration change does not meet the standard;

Among them, the target acceleration change amount Δa is an integer.

The specific operations of step S6) are:

Step S6.1) Determine whether the given initial target acceleration change reaches the standard:

If the standard is met, go to step S6.2);

Otherwise, go to step S6.3);

Step S6.2) Given a new target acceleration change Δa _i :

Δa _i =Δa-i

Among them, the subscript i represents the number of cycles, and Δa represents the initial set target acceleration change;

Continuously reduce and update the value of the target acceleration change, that is, when the initial target acceleration change is given as 100, the next given acceleration change is 99, 98, 97, and so on;

Substitute the updated target acceleration change amount into steps S2) to step S5) for testing, and determine whether the target acceleration change amount reaches the standard; until the target acceleration change amount becomes unqualified, the test ends, and the last target acceleration change amount that meets the standard is as the resolution of the accelerometer 6.

Step S6.3) Given a new target acceleration change Δa _i :

Δa _i =Δa-i

Continuously increase and update the value of the target acceleration change, that is, when the initial target acceleration change is given as 100, the next given acceleration changes are 101, 102, 103, and so on;

Substitute the updated target acceleration change amount into steps S2) to step S5) for testing, and determine whether the target acceleration change amount reaches the standard; until the target acceleration change amount reaches the standard, the test ends, and the target acceleration change amount that reaches the standard is taken as Accelerometer 6 resolution.

The excitation force generated by stepper motor 1 is calculated according to the following formula:

Among them, m is the sum of the masses of a single fixed eccentric block 3 and a single adjustable eccentric block 4, r is the distance between the center of mass of the fixed eccentric block 3/adjustable eccentric block 4 and the rotating shaft of the stepper motor 1, and ω is the rotation of the rotating shaft. Angular velocity, θ _p is the actual angle between the fixed eccentric block 3 and the adjustable eccentric block 4.

In the specific implementation, θ _p is the target angle θ or the adjustment angle θ _c ; the size, model and quality of the fixed eccentric block 3 and the adjustable eccentric block 4 are the same, and the centers of mass of the fixed eccentric block 3 and the adjustable eccentric block 4 are respectively The distance from the stepper motor 1 axis is also the same.

At the target angle θ, the sinusoidal component a of the acceleration signal of the 6-sensitive axis of the accelerometer undergoing linear reciprocating vibration is processed according to the following formula:

Among them, M is the total mass of the optical platform 2, m is the sum of the masses of a single fixed eccentric block 3 and a single adjustable eccentric block 4, r is the distance between the center of mass of the fixed eccentric block 3 and the rotation axis of the stepper motor 1, ω is the rotation angular velocity of the rotating shaft, θ is the target angle, t is the rotation time of the rotating shaft, is the angle between the angular bisectors of the fixed eccentric block 3 and the adjustable eccentric block 4 and the sensitive axis of the accelerometer 6, eta is the horizontal vibration isolation efficiency of the optical platform 2 at the frequency f of the sinusoidal component of the acceleration signal of linear reciprocating vibration.

Claims (9)

1. An accelerometer resolution testing device using the excitation force of a double eccentric motor, which is characterized by: It includes an eccentric module, a signal acquisition module, an optical platform (2), a stepper motor driver (5) and a terminal computer (8); the optical platform (2) is placed on the ground, and the two eccentric modules are fixedly installed on the optical platform (2) On the upper surface of the module, one end of the signal acquisition module is placed on the optical platform (2), the other end of the signal acquisition module is electrically connected to the terminal computer (8), and the input end of the eccentric module is connected to the output end of the terminal computer (8). are connected through the stepper motor driver (5). 2. An accelerometer resolution testing device utilizing the excitation force of a double eccentric motor according to claim 1, characterized in that: the eccentric module includes a stepper motor (1), a fixed eccentric block (3) and Adjustable eccentric block (4); the stepper motor (1) is fixedly installed on the upper surface of the optical platform (2), and the rotating axis of the stepper motor (1) is perpendicular to the upper surface of the optical platform (2), and the fixed eccentric block ( 3) and the adjustable eccentric block (4) are located above the optical platform (2), and the top of the rotating shaft of the stepper motor (1) is connected to the eccentric position of the fixed eccentric block (3) and the adjustable eccentric block (4). Both the fixed eccentric block (3) and the adjustable eccentric block (4) make uniform circular motion around the rotating shaft of the stepper motor (1). The pulse input end of the stepper motor (1) and the terminal computer (8) are connected by a stepper Motor driver (5) connection. 3. An accelerometer resolution testing device utilizing the excitation force of a double eccentric motor according to claim 2, characterized in that: the signal acquisition module includes an accelerometer (6) and a signal acquisition system (7), The accelerometer (6) is placed on the optical platform (2), and the output end of the accelerometer (6) and the terminal computer (8) are connected through the signal acquisition system (7); The two eccentric modules are symmetrically distributed with the sensitive axis of the accelerometer (6) as the symmetrical axis, and the connection line of the stepper motor (1) in the two eccentric modules is perpendicular to the sensitive axis of the accelerometer (6). 4. An accelerometer resolution testing method using the excitation force of a double eccentric motor applied to the device of any one of claims 1 to 3, characterized in that it includes the following steps: Step S1) Install the two eccentric modules on the optical platform (2) axially symmetrically with the sensitive axis of the accelerometer (6) as the symmetry axis, and then set the target acceleration change amount Δa; Step S2) Obtain the amplitude of the sinusoidal component of the digital electrical signal at the target angle: Step S2.1) Given the target included angle θ, and adjust the angle between the fixed eccentric block (3) and the adjustable eccentric block (4) to the target included angle θ; Step S2.2) Under the target included angle, control the stepper motor (1) shaft to rotate, then the optical platform (2) and accelerometer (6) sensitive shaft vibration, and then use the terminal computer (8) to obtain the target included angle The amplitude of the sinusoidal component of the digital electrical signal, and the amplitude of the sinusoidal component of the current digital electrical signal is used as the initial amplitude; Step S3) Obtain the amplitude of the sinusoidal component of the digital electrical signal under the adjusted angle: Step S3.1) According to the given target acceleration change Δa and the target included angle θ, determine the adjustment angle θ _c , and then adjust the position of the adjustable eccentric block (4) so that the fixed eccentric block (3) and the adjustable eccentric The angle between the blocks (4) becomes the adjustment angle θ _c ; Step S3.2) Under the adjusted included angle θ _c , control the rotation of the stepper motor (1) shaft, and then the optical platform (2) and accelerometer (6) are sensitive to shaft vibration, and use the terminal computer (8) to obtain the adjusted included angle. The amplitude of the sinusoidal component of the digital electrical signal, and the amplitude of the sinusoidal component of the current digital electrical signal is used as the adjustment amplitude; Step S3.3) Process according to the following formula to obtain the amplitude difference at the adjustment angle θ _c : Amplitude difference = adjustment amplitude – initial amplitude Step S4) Repeat steps S2) to step S3) multiple times to obtain amplitude differences under different adjustment angles θ _c , and obtain the average of all amplitude differences as the target average amplitude difference corresponding to the target acceleration change Δa; Step S5) Compare the target acceleration change amount Δa with the corresponding target average amplitude difference to determine whether the given target acceleration change amount is the target acceleration change amount that meets the standard; Step S6) Repeat steps S1) to step S5) multiple times to obtain several target acceleration changes, and select the minimum value among the target acceleration changes as the resolution of the accelerometer (6). 5. A kind of accelerometer resolution testing method utilizing the excitation force of a double eccentric motor according to claim 4, characterized in that: in the steps S2.2) and S3.2), the stepper motor ( 1) The rotating shaft rotates, then the optical platform (2) and the accelerometer (6) sensitive shaft vibrates, and then the specific steps of using the terminal computer (8) to obtain the amplitude of the sinusoidal component of the digital electrical signal are: First, the terminal computer (8) controls the rotating shafts of the two stepper motors (1) to run in opposite directions and at the same speed through the stepper motor driver (5). After the rotating shaft of the stepper motor (1) rotates, it drives the fixed eccentric block (3 ) and the adjustable eccentric block (4) move and generate an exciting force. The exciting force drives the optical platform (2) to vibrate. After the optical platform (2) vibrates, it drives the sensitive axis of the accelerometer (6) to vibrate in a straight line; Then, the accelerometer (6) converts the acceleration signal under linear reciprocating vibration into an analog electrical signal, and inputs it into the signal acquisition system (7). The signal acquisition system (7) converts the input analog electrical signal into a digital electrical signal for transmission In the terminal computer (8), the terminal computer (8) is used to process and separate the signal sinusoidal component in the digital electrical signal, and obtain the amplitude of the corresponding sinusoidal component of the digital electrical signal at the current angle. 6. A kind of accelerometer resolution testing method utilizing the excitation force of a double eccentric motor according to claim 4, characterized in that: in step S3.1), according to the given target acceleration change amount Δa and the target The included angle θ, the specific steps to determine and adjust the included angle θ _c are: The adjustment angle θ _c is obtained according to the following formula: θ _c =θ + Δθ Among them, Δθ is the target angle increment, A is the amplitude of the sinusoidal component of the acceleration signal a at the target angle θ, Δa is the given target acceleration change, and θ is the given target angle. 7. A kind of accelerometer resolution testing method utilizing the excitation force of a double eccentric motor according to claim 4, characterized in that: the specific operation of step S5) is: Step S5.1) Compare the target acceleration change Δa obtained in step S4) with the corresponding target average amplitude difference to determine whether the target acceleration change Δa reaches the standard: If 50%＜target average amplitude difference/target acceleration change＜150%, it means that the target acceleration change is the target acceleration change that meets the standard; Otherwise, it means that the target acceleration change amount is a target acceleration change amount that does not meet the standard; The target acceleration change amount Δa is an integer. 8. An accelerometer resolution testing method using the excitation force of a double eccentric motor according to claim 5, characterized in that: the excitation force generated by the stepper motor (1) is processed according to the following formula: Among them, m is the sum of the masses of a single fixed eccentric block (3) and a single adjustable eccentric block (4), r is the distance between the center of mass of the fixed eccentric block (3) and the rotating shaft of the stepper motor (1), and ω is The angular velocity of the rotating shaft, θ _p, is the actual angle between the fixed eccentric block (3) and the adjustable eccentric block (4). 9. An accelerometer resolution testing method using the excitation force of a double eccentric motor according to claim 6, characterized in that: at the target angle θ, the sensitive axis of the accelerometer (6) vibrates in a straight line. The acceleration signal a is processed according to the following formula: Among them, M is the total mass of the optical table (2), m is the sum of the masses of a single fixed eccentric block (3) and a single adjustable eccentric block (4), r is the center of mass of the fixed eccentric block (3) and the stepper motor (1) The distance between the rotating shafts, ω is the angular velocity of the rotating shafts, θ is the target angle, t is the rotation time of the rotating shafts, is the angle between the angular bisector of the fixed eccentric block (3) and the adjustable eccentric block (4) and the sensitive axis of the accelerometer (6), eta is the optical platform (2) at the frequency of the sinusoidal component of the acceleration signal of linear reciprocating vibration ) Horizontal vibration isolation efficiency.