CN104949691A - MEMS inertial component rotation-modulation testing system based on ultrasonic motor - Google Patents

Abstract

The invention discloses an MEMS inertial component rotation-modulation testing system based on an ultrasonic motor. The MEMS inertial component rotation-modulation testing system comprises a rotary table, an inertial component, a wireless transmission unit, a data processing unit and an upper computer. The rotary table comprises a base and further comprises a coded disc, the ultrasonic motor, a table top, a driver and a bearing main shaft which are arranged inside a rotary table shell in a sleeved mode, wherein the bearing main shaft is arranged in the center of the base. The coded disc and the ultrasonic motor are coaxially arranged on the bearing main shaft, and a rotating shaft of the ultrasonic motor is fixedly connected with the table top. The upper computer sends signals to the data processing unit and outputs drive control instructions. The driver of the rotary table drives the ultrasonic motor to rotate, drives the bearing main shaft to rotate and drives the coded disc and the table top to coaxially rotate. After the inertial component obtains the angular rate information of the rotary table, the angular rate information is transmitted to the data processing unit through the wireless transmission unit to carry out strapdown resolving, and a resolving result is fed back to the upper computer. The MEMS inertial component rotation-modulation testing system has the advantages of being high in interference resisting capability, good in electromagnetic compatibility, wide in environmental application range and small and being integrated.

Description

MEMS inertial device rotation modulation test system based on ultrasonic motor

technical field

The invention relates to a MEMS inertial device rotation modulation test system based on an ultrasonic motor, and belongs to the technical field of aerospace positioning, navigation and control.

Background technique

In recent years, as micro-MEMS technology and rotational modulation technology have become more and more mature, the rotational modulation system based on MEMS inertial navigation devices has developed rapidly, that is, the rotational modulation of MEMS inertial components is carried out by introducing a rotating mechanism, thereby improving low-precision, low-cost Performance of MEMS inertial navigation devices. At present, the MEMS rotary modulation technology in foreign countries is relatively mature, and the domestic research started relatively late, especially for the rotary modulation turntable of the system, its control accuracy, volume, power consumption and other performance indicators still have a certain gap with the foreign technical level. From the information found, the National University of Defense Technology was the first to carry out physical research on rotary modulation technology and was relatively leading. In 2007, a prototype of a rotary strapdown inertial navigation system was developed, but the accuracy was not ideal. Single-axis rotary ship test navigation The error is about 17n mile/24h, the static navigation accuracy of the laboratory is better than 1n mile/24h, and the error about the dual-axis rotation is not given. It can be seen that there is still a lot of work to be done in this regard.

At present, some literatures have analyzed the selection of the rotation axis of the single-axis rotation motion, the influence of the rotation rate on the error modulation effect and the evaluation criteria of the rotation scheme, and then on this basis, the single-axis rotation SINS in different rotation The error modulation mechanism of the inertial measurement component is studied under the motion scheme, and finally the error of different rotation motion schemes is compared by simulation analysis. There are also literatures that propose an improved single-axis rotation scheme that installs the IMU obliquely. It is analyzed in principle that this scheme can completely eliminate the inertial device errors in three directions, and the time synchronization between the information of the indexing mechanism and the information of the fiber optic gyroscope is analyzed. The influence of the delay time on the attitude error of the rotary strapdown inertial navigation system is deduced, and a delay time measurement method and compensation strategy are given, and related experiments are carried out to verify.

In addition, according to the error characteristics of MEMS devices, a rotation modulation scheme suitable for the strapdown inertial navigation system of MEMS devices was selected and a prototype was independently developed. Static and vehicle experiments show that the rotation modulation can significantly suppress the influence of MEMS device constant error on navigation accuracy, the accuracy of pitch and roll attitude is increased by 5 times, and the accuracy of speed and position is increased by nearly 10 times within 200s. Other literatures have designed the tumbling method of the gyroscope static drift test, the constant speed test and the angular vibration test of the dynamic drift test using a high-precision single-axis turntable. The influence of the test turntable rate accuracy and rate stability on the gyro test is analyzed, and the automatic compensation of the turntable base tilt is proposed, and the benefits of the high angular velocity of the high-precision single-axis turntable on the gyro drift test are verified. In addition, existing tests have shown that the output of MEMS devices will be seriously affected under strong magnetic fields, and the magnetic field in the direction of the main axis of conventional electromagnetic-based motors happens to be the largest, so it is especially not suitable for error modulation of MEMS devices.

Although the current MEMS technology has been gradually improved, it still has problems. Due to the limitations of motors, drivers and other equipment, the traditional rotary modulation turntable leads to low system control accuracy, large volume, high power consumption, strong residual magnetism, easy loss of lock when power is off, and inflexible transmission methods in the system, which makes the system unfavorable. Realize miniaturization and integration.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, provide a MEMS inertial device rotation modulation test system based on an ultrasonic motor, and solve the problems of low control accuracy, large volume, high power consumption, and strong residual magnetism in the existing system. It has the advantages of strong anti-interference ability, good electromagnetic compatibility, wide range of environmental adaptability, miniaturization and integration, etc.

The present invention specifically adopts the following technical solutions to solve the above technical problems:

A MEMS inertial device rotation modulation test system based on an ultrasonic motor, including a turntable, an inertial device, a wireless transmission unit, a data processing unit, and a host computer. , a table, a driver and a bearing main shaft; wherein the bearing main shaft is installed at the center of the base, the code disc and the ultrasonic motor are coaxially installed on the bearing main shaft, and the rotating shaft of the ultrasonic motor is fixedly connected to the table; the driver and the ultrasonic motor input terminal connection, the inertial device is set at the center of the table; the host computer is used to send control signals; the data processing unit is used to receive control signals and generate drive control instructions; the driver is used to drive the ultrasonic motor according to the control instructions Rotate, and drive the bearing spindle, the code disc, and the table to rotate coaxially; the inertial device is used to obtain the angular rate information of the turntable and transmit it through the wireless transmission unit; the data processing unit is used to process the received angular rate information Perform strapdown calculations, and feed back the obtained calculation results to the host computer.

Further, as a preferred technical solution of the present invention: the inertial device includes a MEMS gyroscope and an accelerometer.

Further, as a preferred technical solution of the present invention: the angular rate information includes angular rate, angle and rotational angular acceleration.

Further, as a preferred technical solution of the present invention: the wireless transmission unit is a wireless Bluetooth module.

Further, as a preferred technical solution of the present invention: the data processing unit is a computer.

Further, as a preferred technical solution of the present invention: the computer adopts an embedded computer.

The present invention adopts above-mentioned technical scheme, can produce following technical effect:

(1) The ultrasonic motor-based MEMS inertial device rotation modulation test system provided by the present invention, based on the development and application of new ultrasonic motor technology, develops an ultrasonic motor modulation turntable, and combines wireless transmission technology, through simulation analysis and verification algorithms, to achieve Rotary modulation function of the system. The turntable not only overcomes the difficulties of traditional turntables such as large volume, high power consumption, low precision, and large residual magnetism, but also has the advantages of strong anti-interference ability, good electromagnetic compatibility, wide environmental adaptability, miniaturization and integration, etc. The later development of high-precision, low-cost MEMS rotary modulation system and MEMS inertial navigation system provides strong technical support.

(2) Based on the ultrasonic motor turntable and MEMS inertial devices, the ultrasonic motor turntable developed by the present invention is used to modulate the MEMS gyroscope. Compared with the traditional turntable, the modulation accuracy can be improved without strong magnetic interference, and the control accuracy is high.

(3) The system takes the embedded computer as the core control board to complete the construction of the rotary modulation system, realize the above rotary modulation system through the physical object, and complete the system test experiment. Through the analysis of the experimental results, the influence of the ultrasonic motor turntable on the rotation modulation of the MEMS gyro can be accurately verified, and technical support can be provided for the later development of a high-precision, low-cost MEMS rotary inertial navigation system.

Description of drawings

FIG. 1 is a block diagram of the MEMS inertial device rotation modulation testing system based on an ultrasonic motor according to the present invention.

Fig. 2 is a schematic diagram of the mechanism of the repeater of the present invention.

Explanation of the labels: 1-base, 2-code disc, 3-ultrasonic motor, 4-table, 5-driver, 6-housing, 7-bearing spindle.

Detailed ways

Embodiments of the present invention will be described below in conjunction with the accompanying drawings.

As shown in Figure 1, the present invention designs a MEMS inertial device rotation modulation test system based on an ultrasonic motor, including a turntable, an inertial device, a wireless transmission unit, a data processing unit, and a host computer, wherein the structure of the turntable is shown in Figure 2 As shown, it includes a base 1 and a code disc 2 nested in the turntable shell 6, an ultrasonic motor 3, a table 4, a driver 5 and a bearing main shaft 7; wherein the bearing main shaft 7 is installed at the center of the base 1, and the code The disk 2 and the ultrasonic motor 3 are coaxially installed on the bearing main shaft 7, and the rotating shaft of the ultrasonic motor 3 is fixedly connected to the table 4; the driver 5 is connected to the input end of the ultrasonic motor 3, and the inertial device is arranged at the center of the table 4; The upper computer is used to send control signals; the data processing unit is used to receive control signals and generate drive control instructions; the driver is used to drive the ultrasonic motor to rotate according to the control instructions, and drive the bearing spindle, code disc, and table to perform coaxial Rotate; the inertial device is used to obtain the angular rate information of the turntable and transmit it through the wireless transmission unit; the data processing unit is used to perform strapdown calculation on the received angular rate information, and feed back the obtained solution result to the host computer.

The principle is: the upper computer sends a control signal to the data processing unit, and the data processing unit outputs a drive control command; the driver 5 of the turntable drives the ultrasonic motor 3 to rotate according to the control command, driving the bearing spindle 7 to rotate and the code disc 2 and the table 4 Coaxial rotation; the inertial device obtains the angular rate information of the turntable, and transmits it to the data processing unit through the wireless transmission unit for strapdown calculation; the data processing unit feeds back the calculation result to the host computer.

Furthermore, MEMS gyroscopes and accelerometers can be used for inertial components in the system. In order to more clearly analyze the modulation characteristics of rotation on the errors of inertial components, ADI’s low-precision MEMS gyroscopes are selected as system angular rate sensitive components. The gyroscopes are connected through RS232 The interface outputs sensitive angular rate information in real time in the form of digital signals. And select the accelerometer to measure the rotational angular acceleration of the turntable. Compared with the traditional turntable, the system can improve the modulation accuracy and has no magnetic interference, and the control accuracy is high.

On this basis, in the system, the MEMS gyroscope and accelerometer components directly output the angular rate and specific force information in the coordinate system of the inertial measurement component, which needs to be transformed by the conversion matrix from the coordinate system of the inertial measurement component to the carrier coordinate system Convert to the carrier coordinate system, and then solve the navigation parameters of the carrier through the data processing module. According to the navigation parameters, it can be verified that the system's navigation accuracy is effectively improved on the basis of inertial devices.

When the system realizes data transmission, the wireless Bluetooth module can be used to reduce the complexity of the system hardware through wireless transmission and realize reliable transmission in wireless mode.

Moreover, the data processing unit in the system, whose main function is to realize data processing, may use a computer. And the computer is embedded, and the FPGA control board can be used to realize functions such as control of the rotating mechanism, serial communication with the sensor, navigation strapdown solution, display and storage. Turntable control and strapdown calculation are integrated control, and there is usually an open loop between turntable control and device accuracy: the control command only guarantees the accuracy of the turntable, this system associates the device accuracy with the turntable control, adding an inertial device accuracy The evaluation module enables the real-time accuracy evaluation of MEMS. If the improvement is less than an order of magnitude, the algorithm is modified through the FPGA to accelerate or change the direction of the turntable.

In summary, the ultrasonic motor-based MEMS inertial device rotation modulation test system provided by the present invention, based on the development and application of new ultrasonic motor technology, develops an ultrasonic motor modulation turntable, and combines wireless transmission technology, through simulation analysis and verification algorithms, to realize the system Rotary modulation function. The turntable not only overcomes the difficulties of traditional turntables such as large volume, high power consumption, and low precision, but also has the advantages of strong anti-interference ability, good electromagnetic compatibility, wide environmental adaptability, miniaturization and integration, etc. , low-cost MEMS rotary modulation system and MEMS inertial navigation system provide strong technical support.

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and can also be made without departing from the gist of the present invention within the scope of knowledge possessed by those of ordinary skill in the art. Variations.

Claims (6)

1. The rotating modulation test system of MEMS inertial devices based on ultrasonic motors is characterized in that: it includes a turntable, an inertial device, a wireless transmission unit, a data processing unit, and a host computer, and the turntable includes a base and a code set in the turntable shell. Disc, ultrasonic motor, table, driver and bearing main shaft; wherein the bearing main shaft is installed at the center of the base, the code disc and the ultrasonic motor are coaxially installed on the bearing main shaft, and the rotating shaft of the ultrasonic motor is fixedly connected with the table; the driver Connected to the input end of the ultrasonic motor, the inertial device is arranged at the center of the table; the host computer is used to send control signals; the data processing unit is used to receive control signals and generate drive control instructions; the driver is used to The command drives the ultrasonic motor to rotate, and drives the bearing spindle, the code disc, and the table to rotate coaxially; the inertial device is used to obtain the angular rate information of the turntable and transmit it through the wireless transmission unit; the data processing unit is used to process the received The angular rate information is used for strapdown calculations, and the obtained calculation results are fed back to the host computer. 2. The MEMS inertial device rotation modulation test system based on the ultrasonic motor according to claim 1, characterized in that: the inertial device includes a MEMS gyroscope and an accelerometer. 3. The MEMS inertial device rotation modulation test system based on the ultrasonic motor according to claim 1, wherein the angular rate information includes angular rate, angle and rotational angular acceleration. 4. The MEMS inertial device rotation modulation test system based on ultrasonic motor according to claim 1, characterized in that: the wireless transmission unit is a wireless Bluetooth module. 5. The ultrasonic motor-based MEMS inertial device rotation modulation testing system according to claim 1, characterized in that: the data processing unit is a computer. 6. The MEMS inertial device rotational modulation test system based on the ultrasonic motor according to claim 5, characterized in that: the computer is an embedded computer.