CN111879320A - Teaching-oriented composite inertial system - Google Patents

Abstract

The invention discloses an open type, modularization and low cost composite inertial system for teaching, which comprises an inertial component, a signal acquisition control board and an upper computer, wherein the inertial component comprises a shell and an inertial module arranged in the shell, the shell is square, each surface of the shell is provided with a transparent observation window, the inertial module comprises a table body, an accelerometer and a gyroscope which are arranged on the table body, a rotating frame for mounting the table body, a motor for driving the rotating frame, a motor driver and a slip ring, and the rotating frame is movably arranged in the slip ring; the signal acquisition control panel comprises an I/F circuit board, an ARM control panel and a communication panel, the I/F circuit board acquires data information of the inertia assembly, the ARM control panel carries out real-time data communication with the I/F circuit board through synchronous serial communication, and the communication panel and an upper computer are in wireless connection and carry out data transmission in real time. The teaching and the research of the inertial system are convenient.

Description

Teaching-oriented composite inertial system

Technical Field

The invention belongs to the technical field of inertia measurement, and particularly relates to a teaching-oriented composite inertia system.

Background

The inertial measurement system utilizes inertial sensors such as gyroscopes and accelerometers and an electronic computer to measure the acceleration of the vehicle relative to the ground motion in real time to determine the vehicle position and the earth gravitational field parameters. The system is developed on the basis of an inertial navigation system and is divided into a local horizontal inertial system and a space stabilizing system. The first category of local horizontal north-seeking inertial systems is commonly used.

A strap-down inertial system with a rotating mechanism, called a composite inertial system for short, is a novel inertial navigation system between a strap-down inertial system and a platform inertial system which is provided domestically in recent years. In the aspect of system composition, compared with the traditional strapdown inertial navigation system, the combined inertial navigation system is additionally provided with a set of rotating mechanism; compared with the traditional platform inertia system, the combined type inertia system greatly reduces the rotation precision of the rotating mechanism and greatly reduces the processing difficulty. In terms of performance, the composite inertial system has a self-calibration function by combining a calibration algorithm after adopting a rotating mechanism, and solves the problem that the inertial system needs to be calibrated by a high-precision turntable regularly; the north-seeking precision can be high; the rotation mechanism can be used for movement, and the navigation precision which is multiple times better than that of the traditional strapdown inertial system can be obtained.

The hybrid inertial system has been applied to aircraft guidance and control systems and vehicle positioning, directional and aiming systems, wherein a representative product is a three-self strapdown inertial set with self-calibration, self-alignment and self-detection functions. Many organizations and research institutions are beginning to invest in energy, develop research and application of the hybrid inertial system, and perform related work.

The composite inertial systems that have been developed at present are expensive, and although they are greatly reduced compared to the platform-type inertial systems, the large and millions of prices make many users with potential application requirements prohibitive, and are only applied in some special situations. Meanwhile, the existing composite inertial system is poor in openness and low in modularization degree, is generally a customized product, is difficult for a user to develop further application and development, and is inconvenient for teaching. Based on the teaching experimental equipment patent based on the stable platform invented by Lemunson and the like at the university of Zhongshan, the combination of the inertial group module, the upper computer and the control module is utilized, the experimental efficiency is improved, and the teaching process is accelerated. But does not address the teaching problems of inertial systems. The invention relates to an aircraft navigation, guidance and control technology teaching experimental device which is invented by people in China, liberating the great celebration of the national defense science and technology university, mainly faces to the whole system simulation of a missile control system, has complex composition and does not provide a solution aiming at an inertial system. The invention relates to a strapdown inertial navigation system with self-calibration, self-alignment and self-diagnosis functions, which is invented by Liuyuan of Hubei institute of aerospace technology research, and a patent invented by Younguan surrounding 'three self-inertial units', and mainly aims at aircraft navigation design, and is complex in equipment composition, high in cost, poor in openness and difficult to directly use for teaching.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: an open, modular, low cost composite inertial system for teaching is provided.

In order to solve the technical problems, the invention provides the following technical scheme: a teaching-oriented composite inertial system comprises an inertial component, a signal acquisition control board and an upper computer, wherein the inertial component comprises a shell and an inertial module arranged in the shell, the shell is square, each surface of the shell is provided with a transparent observation window, the inertial module comprises a platform body, an accelerometer and a gyroscope which are arranged on the platform body, a rotating frame used for installing the platform body, a motor used for driving the rotating frame, a motor driver and a slip ring, and the rotating frame is movably arranged in the slip ring; the signal acquisition control panel comprises an I/F circuit board, an ARM control panel and a communication panel, the I/F circuit board acquires data information of the inertia assembly, the ARM control panel carries out real-time data communication with the I/F circuit board through synchronous serial communication, and the communication panel and an upper computer are in wireless connection and carry out data transmission in real time. The gyroscope senses angular velocity or angular increment information and outputs the information outwards through a digital or pulse signal, the I/F circuit board converts visual acceleration information sensed by the accelerometer into a pulse or a digital signal and outputs the pulse or the digital signal outwards, the pulse or the digital signal is sent to the signal acquisition control circuit in real time through a serial bus, the signal acquisition control circuit processes received signals and outputs the processed signals to the upper computer, and the upper computer provides an operation interface, a data analysis and display interface and a data storage function of a user side.

As a further improvement of the above technical solution:

the communication board comprises a Bluetooth receiving module, an HDLC processing module and a microcontroller, wherein the Bluetooth receiving module and the microcontroller transmit and communicate information through the HDLC processing module, and the HDLC processing module comprises a control register, a state register, a data memory and an HDLC protocol inner core. The signal acquisition control board adopts an HDLC communication controller based on a Bluetooth wireless interface, can conveniently complete signal communication with an upper computer and a platform body, can conveniently complete parameter binding and program downloading outside an inertia measurement system, is convenient for a user to develop algorithm research, and improves the openness of the system; wiring links are greatly reduced, and system reliability is improved; meanwhile, the high-speed data transmission capability of the HDLC communication controller meets the requirement that an inertial system transmits a large amount of data to the outside at a high speed. Along with the design trend of high integration, high integration and high miniaturization of an inertia measurement system, higher requirements are put forward on data communication among functional modules in the system, and the problems existing in the current common technical scheme are as follows: the use of high-speed parallel transmission has obvious disadvantages in cost, technical risk and anti-electromagnetic interference; the RS485/422 serial communication interface which is widely used at present has low speed and is difficult to meet the technical requirement of high-speed data transmission.

The slip ring is made of carbon fiber reinforced polytetrafluoroethylene materials, a special bearing is used in a high-precision inertial system, the cost is high, the maintenance is complex, and the slip ring synthesized by the carbon fiber reinforced polytetrafluoroethylene materials has the characteristics of low friction coefficient and no need of lubrication.

Three accelerometers are arranged on the outer side of the table body in a space orthogonal mode, and three gyroscopes are arranged on the outer side of the table body in a space orthogonal mode.

The upper computer comprises the following functional modules: the automatic data binding and reading system comprises a data acquisition module, a data storage module, a data display module, a data curve module, a self-calibration calculation module, a self-north-seeking calculation module, a transposition mechanism control module and a parameter binding and reading back module.

Compared with the prior art, the invention has the following beneficial effects:

the teaching-oriented composite inertial system effectively meets the requirements of high-speed serial and synchronous full-duplex data exchange between modules in an inertial measurement product, improves the reliability and stability of data, completes the conversion and processing processes of the data in the FPGA, and is not easily interfered by the outside. By adopting a Bluetooth wireless interface, the transmission rate of a general serial interface chip is improved by dozens of times by the HDLC communication controller.

The method for realizing the high-speed synchronous serial bus by adopting the hardware description language realizes the functions of the wireless Bluetooth control module and the HDLC protocol, can be compatible with flexibility and universality, can realize multi-path real-time parallel processing, and has short design and development period.

The signal acquisition control board can output original pulses of a gyroscope and original pulse information of an accelerometer and can output angle information of a rotating mechanism; the inner frame and the outer frame of the rotating mechanism can be controlled to rotate at a set speed by receiving an external indexing mechanism control command. By opening bottom layer data, an inertial measurement unit software communication and rotating mechanism control interface is provided, a user can design a rotating process of the rotating mechanism according to self requirements, acquire inertial measurement unit data and complete algorithm verification, such as a self-north-seeking algorithm, a self-calibration algorithm, a navigation algorithm and the like.

The signal acquisition control board adopts an HDLC processing module based on a Bluetooth wireless interface, can conveniently complete signal communication with an upper computer and a platform body, can conveniently complete parameter binding and program downloading outside an inertia measurement system, is convenient for a user to develop algorithm research, and improves the openness of the system; wiring links are greatly reduced, and system reliability is improved; meanwhile, the high-speed data transmission capability of the HDLC processing module meets the requirement that the inertial system transmits a large amount of data to the outside at high speed.

The upper computer software has a plurality of working interfaces: the original data acquisition mode can acquire and store original pulses of the gyroscope and original pulse information of the accelerometer; the motor control mode realizes the independent control function of the inner frame and the outer frame indexing mechanism; a design self-calibration offline calculation module and a self-north-seeking offline calculation module are reserved, so that self-calibration and self-north-seeking functions can be completed;

in the aspect of structure, the cover plates of the inertial system are all made of transparent plastic shells, so that inertial devices, IF circuits, power modules, signal processing circuits, rotating frames, motor control circuits and the like in three directions can be clearly observed from the outside;

the shafting supports between the outer ring and the engine base and between the inner ring and the outer ring adopt carbon fiber reinforced polytetrafluoroethylene slip rings, the structure is simple, the shafting is convenient to disassemble and assemble, lubricating oil is not needed, the maintenance is convenient, and the cost is low.

The modular integrated design integrates the motor and the angle measuring device, the three accelerometers form independent components, and the power module forms independent components, so that the power module is convenient to disassemble, assemble and maintain.

Drawings

FIG. 1 is a schematic view of the housing structure of the present invention;

FIG. 2 is a schematic view of an inertial module according to the present invention;

FIG. 3 is a schematic structural diagram of a communication board system according to the present invention;

FIG. 4 is a schematic diagram of a HDLC processing module system according to the present invention.

Reference numerals: 11. a housing; 12. an inertial module; 111. a transparent viewing window; 121. a table body; 122. an accelerometer; 123. a gyroscope; 124. a rotating frame; 125. a motor; 129. a power module.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The technical solutions of the embodiments of the present invention can be combined, and the technical features of the embodiments can also be combined to form a new technical solution.

As shown in fig. 1 to 4, the composite inertial system for teaching of this embodiment includes an inertial component, a signal acquisition control board and an upper computer, the inertial component includes a housing 11 and an inertial module 12 disposed in the housing 11, the housing 11 is square, and each surface is provided with a transparent viewing window 111, the inertial module 12 includes a table 121, an accelerometer 122 and a gyroscope 123 disposed on the table 121, a rotating frame 124 for mounting the table 121, a motor 125 for driving the rotating frame 124, a motor driver, and a slip ring, the rotating frame 124 is movably mounted in the slip ring; the signal acquisition control panel includes I/F circuit board, ARM control panel and communication board, and the data information of inertia subassembly 1 is gathered to the I/F circuit board, and the ARM control panel carries out real-time data and exchanges through synchronous serial communication and I/F circuit board, and the communication board carries out data transmission in real time through wireless connection with the host computer. The table body 121 is further provided with a power supply module 129, the power supply module 129 is used for supplying power to the accelerometer 122 and the gyroscope 123, the sensitive angle increment information of the gyroscope 123 is output outwards as digital signals and is sent to the signal acquisition control board in real time through a serial bus, the signal acquisition control board processes the received signals and outputs the signals to the upper computer, and the upper computer provides an operation interface, a data analysis display interface and a data storage function of a user side. The signal acquisition circuit adopts a HDLC communication controller based on a Bluetooth wireless interface, realizes the internal and external transmission of signals, and improves the openness of products. When the signal acquisition control circuit receives self-calibration, self-alignment and self-detection instructions, the locking mechanism is controlled to be unlocked through the bus, the inner frame rotating mechanism and the outer frame rotating mechanism rotate according to a set program, and meanwhile, gyroscope 123 data, accelerometer 122 data and temperature measurement data sent by the signal acquisition circuit are received through the serial bus.

The signal acquisition control board processes and resolves the data to obtain self-calibration parameters, self-alignment results and self-detection information, and the self-calibration, self-alignment and self-detection functions of the inertial measurement unit are realized. After the three self functions are completed, the inertia module 12 enters a navigation working mode; the signal acquisition control board controls the rotation of the rotating frame 124, so that the inertial module 12 works in a specific navigation state. And the signal acquisition control board acquires the original pulse data, the I/F and the gyro temperature of the three-way gyroscope 123 and the three-way accelerometer 122 acquired by the I/F circuit board through 422 synchronous serial communication of the I/F circuit board. Meanwhile, the original data is subjected to communication output through temperature compensation and FIR digital filtering; and establishing a dynamic error model according to the gyroscope 123 and the accelerometer 122, and outputting an angle increment and an apparent acceleration increment by adopting a dynamic compensation filtering method. The ARM control board selects STM32H743IITX as a chip of Italian semiconductor company, and the technical parameters of the chip meet the design requirements of products.

The communication board comprises a Bluetooth receiving module, an HDLC processing module and a microcontroller, the Bluetooth receiving module and the microcontroller transmit and communicate information through the HDLC processing module, and the HDLC processing module comprises a control register, a state register, a data memory and an HDLC protocol kernel. The HDLC protocol is a high-level data link control procedure oriented to bits, has strong error detection function and synchronous transmission characteristics, and ensures reliable transmission of data. The HDLC protocol does not require a physical layer, can achieve very high transmission speed by adopting a proper level interface standard, and has the characteristics of flexible operation, high reliability and high speed.

The whole system adopts wireless Bluetooth signals as interfaces of a physical layer and a data link layer of data communication to connect high-speed data exchange among all unit modules in the inertial measurement system. The hardware adopts a processing framework of FPGA + DSP, wherein adopted Xilinx Virtex7 series FPGA chips are integrated with a Bluetooth wireless control module in the chips, and point-to-point transmission is realized by using the Bluetooth 5.0 standard. The Bluetooth module works in a 2.4G wireless frequency band, the influence of various factors on wireless receiving and transmitting can be avoided, and the baud rate can be flexibly set according to different high-speed data transmission conditions. The control register is responsible for updating and recording state information related to the receiving and sending work of the HDLC processing module; the state register is used for identifying an event set by the microcontroller to the working mode of the HDCL processing module; the data memory adopts an FIFO (first input-first output) type double-port memory to cache the communication data between the microcontroller and the HDLC processing module; the HDLC protocol kernel adopts an FPGA kernel designed according to the coding rule of standard HDLC, and kernel hardware is implanted into an FPGA chip. The microcontroller selects a TI company C6000 series DSP processor, and completes the access to the cache data area in the HDLC processing module by utilizing the cooperation of parallel data and an address bus, wherein the access comprises the write operation of writing the communication data to be sent into the cache data area and the read operation of reading the received data in the cache data area.

The data receiving process of the whole system is as follows: the communication data received by the external inertia module 12 by the Bluetooth receiving module is analyzed according to the HDLC protocol, is stored in the data memory after being decoded by the HDLC protocol kernel, and sends an interrupt request signal to the embedded microcontroller to indicate that a frame of correct HDLC data is received. The embedded microcontroller acquires the receiving state information by inquiring the receiving state register and then accesses the data memory by utilizing the parallel data and the address bus to finish the reading of the data.

The data transmission process of the whole system is as follows: and writing the data to be sent to the microcontroller into a sending data memory in sequence, configuring the length information of the data packet in a sending control register, and finally starting a sending command by the microcontroller. After the HDLC processing module receives the sending instruction, the internal HDLC protocol kernel encodes the data in the sending data memory and transmits the processed data to the wireless Bluetooth transceiver bit by bit. And when the data of one frame with the specified length is completely transmitted according to the Bluetooth PHY protocol, the HDLC processing module updates the transmission status register to indicate that the data transmission is completed.

The slip ring is made of carbon fiber reinforced polytetrafluoroethylene materials, and has the characteristics of low friction coefficient, no need of lubrication and low price.

Three accelerometers 122 are arranged outside the table body 121 in a space orthogonal mode, and three gyroscopes 123 are arranged outside the table body 121 in a space orthogonal mode.

The upper computer comprises the following functional modules: the device comprises a data acquisition module, a data storage module, a data display module, a data curve module, a self-calibration calculation module, a self-north-seeking calculation module, a transposition mechanism control module and a parameter binding read-back module. The upper computer software adopts the joint design of visual studio6.0 and BCGCBPro6.0, the operating environment is a Windows operating system, and the functions of data acquisition, data display, curve drawing, data storage, data calculation, parameter binding and the like are realized; and a visual human-computer interface is designed by software, so that the test operation of the user on the inertial measurement unit is facilitated. Data acquisition is mainly carried out through RS422 high-speed serial ports, in order to avoid the occurrence of data acquisition frame loss caused by Windows multitask event interference, software adopts a multithreading design technology, serial port data acquisition independently occupies a thread with the highest priority, and stable and reliable data acquisition under a Windows system is ensured. And the upper computer software reserves a self-calibration off-line calculation and self-north-seeking off-line calculation module, and when the inertial measurement unit software does not realize the self-calibration and self-north-seeking calculation functions, the upper computer software completes the self-calibration calculation and the self-north-seeking calculation functions. The part of functions is designed into an automatic execution mode, namely, after the self-calibration process is finished, the upper computer software automatically calls a calibration calculation function, and after the calculation is finished, the calibration result is automatically stored and automatically downloaded into the inertial measurement unit. If the inertial measurement unit software realizes the self-calibration and self-north-seeking calculation functions, the upper computer software does not perform calibration and north-seeking calculation any more.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (5)

1. A teaching-oriented composite inertial system is characterized in that: the intelligent control device comprises an inertia assembly, a signal acquisition control board and an upper computer, wherein the inertia assembly comprises a shell (11) and an inertia module (12) arranged in the shell (11), the shell (11) is square, each surface of the shell is provided with a transparent observation window (111), the inertia module (12) comprises a table body (121), an accelerometer (122) and a gyroscope (123) which are arranged on the table body (121), a rotating frame (124) used for installing the table body (121), a motor (125) used for driving the rotating frame (124), a motor driver and a slip ring (127), and the rotating frame (124) is movably arranged in the slip ring (127); the signal acquisition control panel comprises an I/F circuit board, an ARM control panel and a communication panel, the I/F circuit board acquires data information of the inertia assembly (1), the ARM control panel carries out real-time data communication with the I/F circuit board through synchronous serial communication, and the communication panel is in wireless connection with an upper computer to carry out data transmission in real time.

2. The teaching-oriented composite inertial system of claim 1, wherein: the communication board comprises a Bluetooth receiving module, an HDLC processing module and a microcontroller, wherein the Bluetooth receiving module and the microcontroller transmit and communicate information through the HDLC processing module, and the HDLC processing module comprises a control register, a state register, a data memory and an HDLC protocol inner core.

3. The teaching-oriented composite inertial system of claim 1, wherein: the slip ring (127) is made of a carbon fiber reinforced polytetrafluoroethylene material.

4. The teaching-oriented composite inertial system of claim 1, wherein: three accelerometers (122) are arranged on the outer side of the table body (121) in a space orthogonal mode, and three gyroscopes (123) are arranged on the outer side of the table body (121) in a space orthogonal mode.

5. The teaching-oriented composite inertial system of claim 1, wherein: the upper computer comprises the following functional modules: the device comprises a data acquisition module, a data storage module, a data display module, a data curve module, a self-calibration calculation module, a self-north-seeking calculation module, a transposition mechanism control module and a parameter binding read-back module.

Images