The abstract takes the inertia component’s inertial navigation/guidance system by the piezoelectricity top and the piezoelectricity accelerometer, has the cost to be low, quality light, anti-impact, reliable higher merit. Is solution which the inertial navigation has studied. The article introduced that realizes the piezoelectricity strapdown inertial navigation system’s platform based on TI Corporation TMS320C5410. The elaboration system’s hardware and the system composition and the design, show in detail the DSP system. The HPI connection, the serial port transmission data as well as the program load from lift and so on use with to realize the method.
Key word piezoelectricity strapdown inertial navigation system DSP Strapdown attitude computation
Introduction
In recent years, the general scientific research worker studied each kind to reduce the piezoelectricity strapdown inertial navigation system’s erroneous method, enabled the piezoelectricity inertia component’s precision to obtain enormous enhancement [1]. this article to introduce one kind practical the piezoelectricity strapdown inertial navigation system plan which realized based on DsP.
1 system’s hardware design
The entire piezoelectricity strapdown inertial navigation system divides into three parts: Piezoelectricity inertia built-up section; Signal connection which and a/d conversion unit are composed of ADS1251 and ADuC834; By TMS320C54lO and so on data processing unit which constitutes. System diagram as shown in Figure 1.
The piezoelectricity inertia combination uses the special-purpose piezoelectricity top and the piezoelectricity accelerometer. By TI Corporation 24, 20 kHz A/D switch ADSl251 completes six group piezoelectricity tops and the piezoelectricity accelerometer’s signal precise sampling, the actual sampling speed is 500 Hz. Uses American Simulation Component Company’s 8 51 MCU microprocessor ADuC834 to make six groups sampling the master-control units. ADuC834 integrated the temperature sensor, 62 KB programmable procedure EEPROM, the timer, as well as I2C compatible SPI and standard serial I/O and so on. Reads the person six groups sampling transform the signal after the SPI way, simultaneously completes the temperature the sampling, after all sampling, obtains the digital signal reads in TMS320C5410 through the HPI connection the data unit. Uses ADuC834 the mouth 0 2 to realize with the mouth with the TMS320C54lO HPI connection is connected, interface circuit as shown in Figure 2.
The data processing unit by TMS320C5410, SST39VF200B and MAX3111E is composed. TMS320C5410 is TI Corporation 54 series DSP processors, the external connection 10 MHz crystal oscillators, through establishes PLL, the operating frequency in 100 MHz, handling ability may achieve l00MIPS. It uses the micro computer working (MP/MC pin earth), external connection SST39VF200B takes the external connection memory. When system initiation, by solidification, in TMS320C5410 internal RoM from lifts the vectoring procedure to load in SST39VF200B the application procedure. TMS320C5410 and ST39VF200B connection as shown in Figure 3.
TMS320C5410 McBSP0 and MAX3111E are connected, complete the serial port data the output. Establishes the McBSP0 work in the SPI driving pattern, carries on the correspondence with MAX311lE. Electric circuit connection as shown in Figure 4.
2 system software designs
2.1 HPl connections
System software including ADuC834 software design and DSP software design. The ADuC834 software part uses the assembly language compilation, completes HPI the initialization, temperature signal gathering, to complete six group signal gathering and the receive, the HPI data transmission through the corresponding pin control and so on. Used the HINT pin signal to complete the bilateral data the synchronization. DSP through writes to the HPIc HINT position I, causes the HINT pin to become the low level, instructed that ADuC834 transmits the recent data frame. ADuC834 reads this low level signal from pin P2.7, finished a data to the hypothesis DSP data area, wrote HPIC again the HINT position, restored the HINT pin is the high level. Then reads to the HPIC in DSPINT position 1, informs DSP to enter the person HPI interrupt receive data. After DSP receives the data, writes l again to the HPIC HINT position, instructs the recent data transmission process.
2.2 master routines
The DSP part’s software uses the C language design, including abundant procedure, HPI interrupt servicing subroutine and timer interruption service subroutine. The master routine completes system’s initialization, including DSP working pattern establishment, storehouse establishment, initialization McBSPO, initialization MAX3111E, establishment timer interruption and so on. Diagram as shown in Figure 5.
2.3 Strapdown attitude computation
The HPI interrupt part completes the data receive at the same time, completes the data computation processing, the ADuC834 data has deposited in the hypothesis several data unit, reads and compares the data to use the quaternion algorithm to carry on the Strapdown attitude computation. Algorithm partial functional module as shown in Figure 6.
2.4 serial data transmissions
Through disposes McBSPO and MAX311lE, realizes angle which, position completes in the timer interruption part calculates, data and so on speed transmissions. Established each 10ms to transmit one time the data, selected the inquiry method to complete the data the transmission.
When system guidance completes McBSPO and the MAX3111E initialization, at the beginning of the McBSP0 beginning the procedure is as follows:
Through inquires the SPCR2 XRDY position and the XEMPTY position may know whether can write the data to McBSP, the polling routine is as follows:
Writes through the transmission data disposes the register to complete MAX3111E the initialization, the procedure is as follows:
void init_max3111e() {
unsigned int flagl=0xO; ;
mcbsp ready();
*DXRl0=0xc801;
// writes disposes the register, the permission transmission buffer spatial interrupt, fosc=3.6864 MHz
// baudrate is 115 200 b/s,8 bit data position, 1 stop position
mcbsp_ready();
};
When transmits the data, is guaranteed that the MAX311E obliterated data, does not need the interrupt mode or the inquiry way, transmits the data again in the MAX3111E buffer free time, the inquiry way transmission data procedure is as follows:
void sendl (unsigned char data) {
unsigned char flag=0×0, datahi, datalow;
while (flag! =0×4801) {// 14th is 1, expression transmission buffer for spatial
mcbsp_ready()
3 procedure’s translations with from lift
Through the JTAG connection, may facilitate by the simulator carries on the debugging to the platform, simultaneously completes the application procedure read-. May establish the corresponding project in the CCS integrated development environment, inducts the .cmd document, the vector.asm document, the storehouse document, the source program and so on. Joins v548 in the translation option, after the translation, produces the corresponding .out document. The entire procedure is smaller than 32 KB, uses C54xx the general Flash fever to write tool C54xx Flash Tool 2.01[2], produces flashburn which the corresponding 16 hex document and the Flash fever write. Out document. Enters flashburn.out in the CCS Intermediate-range, establishes CPU the register DROM position is 0, then the movement, namely completed the procedure fever has written to SST39VF200B.
Conclusion
The piezoelectricity strapdown inertial navigation system platform which realizes based on TMS320C5410, the electric circuit volume is small, the system stability is high. After the test, the overall performance satisfies the error correction, the posture angle and the speed, the acceleration computation request, and provided the strapdown inertial navigation system to realize each algorithm foundation platform.
