计算机系统发展

1、Intern ati onal Conference on Adva nces in Computati onalModeli ng and Simulati onThe semi-physical simulatio n system desig n of micro-satellite based-on HLA Xue Sheng, Xuekui Liu, Zhaowei SunResearch Cen ter of Satellite Tech no logy, Harbin In stitute of Techno logy? Harbin150001?Ch inaAbstractTh

2、e ground simulation validation is an important process during small satellite' sdevelopme nt. Givingcon sideratio n to the characteristics of small satellite and a type of ground simulatio nrequireme nts, a smallsatellite hardware-i n-loop simulatio n system based-on HLA is established. Systemst

3、ructure, the in teracti ondata table, hardware in terface un it and the federal members' flow chart are desig ned.The simulati on andvalidation are done to a certain small satellite through the designed hardware-in-loopsimulati on system.The results show that the simulation system is able to sim

4、ulate dynamics and controlsubsystem, powersupply subsystem and payload subsystem and realize access ing physical equipme ntof con trol subsystemmuch better, and has good practical application value.? 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibilityof KunmingUni versi

5、ty of Scie nee and Tech no logyKeywords: micro-satellite; hardwire-i n-loop; Simulatio n System; HLA.1. In troduct ionWith the developme nt of civil space, high-performa nee civilia n spacecraft aren eeded urge ntly. However,because the private enterprises are limited by financial resources, it'

6、 s impossible totake a large in vestme ntto large output routi ne. In order to gain greater econo mic ben efits through lessin vestme nt, we have toimprove the traditi onal developme nt means that are used to desig n and researchspacecraft. To improve the* Correspo ndi ng author. Tel.: +86-451-86402

7、357.Xue Sheng et al. / ProcediaE-mail address: 802Engin eeri ng 31 (2012) 801-806fun cti onal den sity and the quality, shorte n the research cycle and reduce the research costs, a lot ofsimulati ons and testi ng on the ground are n ecessary duri ng the spacecraft research and developme

8、 nt process,which en sure the success rate duri ng spacecrafts running on-o rbit.The simulati on of satellite system, as an importa nt part of the satellite developme nt, is an effective waywidely used to test and verify the overall satellite parameters of the space missi ons and the satellite syste

9、m.Furthermore, domestic and foreig n space age ncies have proved that the adva need mathematical desig n andsimulati on tech niq ues are importa nt means to improve the performa nee of the spacecraft, en sure thedevelopme nt quality, reduce developme nt costs and risks, shorte n the developme nt cyc

10、le and en sure reliableoperation on-orbit1.Domestic and foreig n scholars have carried out exte nsive research in the spacecraft simulati on system,for example, the Uni versity of Turin( Italy) andAle nia Space have developed theparallel developme ntenvironment to facilitate the parallel developme n

11、tof space missi ons, and theelectrical compa nyCAE(Ca nada) has developed a graphical simulati on platform of spacecraft software environment. Althougha simple mathematical simulation is capable of meeting the needs of mission assessme nt, the tim ing ofsimulation is one of the limited factors. Hard

12、wire-in-Loop Simulation (HIL) means that some kind ofphysical objects n eed accessed by mathematical simulati on systems, hence, the time, in terface, performa neeand other parameters will be verified by the HIL simulatio n platform. I n the refere nee 3, Wang Feng andhis collaborators have establis

13、hed the hardwire-i n-Loop simulatio n platform for the micro-satellite con trolsystem; In the refere nee 4, Chang Tong li and his collaborators have established the hardwire-i n-Loopsimulatio n platform for space dock ing. However, all of these have con sidered their scalability and ope nn ess.Resea

14、rches on data storage and time man ageme nt issues have bee n studied in reference 5 and 6, but thedetails for building large-scale systems simulation and accessing a variety of data or software have not bee nelaborated clearly. As the increasing of collaboration during the process of spacecraft res

15、earch, it ' s a mostpressing issue that an open and scalable hardwire-in-loop simulation platform is required to establish.In view of the above requireme nts, the purpose of this paper is to establish simulatio n platform with ope nand scalable in terface for micro-satellite, which is base-on HL

16、A (High Level Architecture) framework.Therefore, the main work in cludes architecture and in terfaces desig ning for simulati on system, givi ng thesystem-level data flow as well as the specific task requireme nts of a model simulati on, and the n running thecase and gain the simulati on results.2.

17、Framework for simulatio n system based-on HLAIn order to simplify the micro-satellite system developme nt and to achieve the future expa nsion andreuses, comp onent of the system will be tran sferred to modular desig n inaccorda nce with its fun ctio n,which is based-on the characteristics and requi

18、rements of its simulation process. As for the comp onents ofdiffere nt function, its corresp onding simulati on model should be desig ned, and a visual in terface panel isused to con trol and achieve its functions. The federal member is in terc onn ected by LAN, using M? K RTI3.0 as its Run Time Inf

19、rastructure. Lib RTI from RTI is loaded to each of the federal program, the servicewill be exte nded to developers of federati on. The fun ctio n that federal in formatio n excha nge betwee n thefederal members and others is achieved through the HLA in terface.The basic task of hardwire-i n-loop sim

20、ulati on for micro-satellite is to complete validati on for hardwareand software of its subsystem(s). It means subsystems for a micro-satellite will be assig ned to a differe ntcomputer to complete the mathematical simulati on, and the hardware sub-systems will n eed to be verified inphysical form d

21、uri ng the simulati on. The data com muni cati ons betwee n the various subsystems based-onHLA and entire satellite system is built naturally. The hardwire-in-loop simulation fora micro-satellite Xue She ng et al. / Procedia Engin eeri ng 31 (2012) 801-806 803system based-on HLA, including eight sub

22、systems (federations), the simulation host computer, statusdisplay subsystem, dyn amic systems, power subsystem, satellite service subsystem, thermal con trolsubsystem, payload subsystem and data man ageme nt subsystem, Figure 1 shows the block diagram forhardwire-i n-loop simulatio n system.Federat

23、e 6In terface Un itFederate 5Flight missi onsubsystemFederate 7PayloadsubsystemFederate 8Data man ageme ntsubsystemCon trol subsystemSOCFED fileRTI?Run -Time Infrastructure?Federate 1Simulatio n hostcomputerFederate 2Status displayFederate 3Dyn amicsubsystemFederate 4PowersubsystemFig. 1. Block diag

24、ram for simulati on systemThe blocks ' function of hardwire -in-1oop simulation system is described as follows?(1) Simulation host computer taken as the management terminal during simulation is the simulati on corepart to man ageme nt and con trol the en tire models and simulatio n platform. Its

25、 mai n fun ctio ns are as follows:x Subsystems are modeled separately, and host computer for simulati on is used to delete and add thefederati on, so its fun cti ons for the subsystems simulatio n models are in tegrated into an en tirety. Basedo n the parameters from pre-optimized in terface, data c

26、om muni cati on protocols, accord ing to the realfeatures of physical devices, on-board data and con trol flow, the n simulati on and verificati on forSystem-wide and the whole process istake n n aturally.x In additi on to the above, the host computer also the con trol cen ter in the process of dist

27、ributedsimulati on, is used to set simulati on parameters(such as the simulatio n step in terval,the in itial orbitalparameters, the environment perturbati on con sidered in the simulati on, thresholds for the con trol system,etc.).(2) Subsystem of status display can access to satellite status param

28、eters from the HLA/RTI, and then thesimulati on results prese nted to the user by STK anddata sheets. What n eed toexpla in is that statusparameters as men ti oned before in clude orbital parameters, attitude parameters, sen sor parameters andactuator parameters, etc.(3) The main function of dynamic

29、s computer is to solve the orbital dynamics model, attitude dyn amicsmodel, space environment models and sensor models of the satellite.(4) Simulati on computer of power system hasestablished solar array model,battery and powercon troller model based-on MATLAB. Users can complete the satellite power

30、 system desig n and prelim inarysimulati ons. At the same time, module for collecti ng the telemetry parameters and display ing the nu mericalresults using the dyn amic curve of power system is established synchrono usly.(5) Flight missi on system is the importa nt subsystem of data process ing and

31、con trol, the success orfailure of the micro-satellite depe nds on whether its performa nee and timi ng series being correct or notdirectly. The physical object for Hardwire-i n-loop simulati on men ti oned above mainly refers to the flightmissi on system which takes SOC as the primary platform. 804

32、Xue Sheng et al. /Procedia En gi neeri ng 31 (2012) 801-806(6) In terface unit is in termediate computer for data excha nge betwee n physicalhardware and HLA/RTI.Physical equipme nt mainly execut ing attitude and orbitcon trol algorithms, and itshardware platform isSOC.(7) Payload subsystem computer

33、 has established themodels of the satellitepayloads (such as earthremote sensing payload and earth imagi ng payload, etc.), the n has gained itsperforma nee of simulatio n andevaluation. This system is an important foundation for the overall mission analysisduring the integrationmathematical simulat

34、ion of the whole satellite, the system can be linked with thein tegrated simulati on.(8) Data man ageme nt subsystem as a federatio n ofsimulatio n is a key member tostore and accesssimulati on data. Specifically, the simulati on computer possess real-time databaseand complete the dyn amicdata colle

35、ct ion duri ng simulati on.Each simulati on subsystem n eeds to send or receive date. These data isen capsulated as an object classrespectively, and each data corresp onds to an object class attribute. Eight objectclasses of federatio n aredefi ned. These data are maintain ed, published and ordered

36、among federatio n members. The host computerpublishes its simulation object class, which contains the user' s configurationinformation of the simulationsystem, the information of initial parameters and federal information. In order to show the simulati onparameters to the user timely, the simula

37、tion host should order the federate data from Status, Dyn amics,Payload and other federates. Other subsystems are similar to the host computer.3. In terface un it for physical deviceDue to the limited physical device in terface, it' s difficult to access to HLAco-simulati on environmentdirectly.

38、 Hen ce, it is required to desig n hardwarein terface un it for SOC. Thehardware in terface un itsin cludes SOC man ageme nt module, real-time data collect ion module, data conversion module, datadistributi on man ageme nt module, time man ageme nt module, and HLA in terface, as show n in Figure 2.W

39、hile the hardware access to the systems successfully, the in terface betwee n the hardware and HLA isn eeded, and this in terface unit requires achievi ng the follow ing two functions:(1) Function for data format conversion: in HLA, i nformatio n in teractive is achievedby updat ing andreflect ing t

40、he objects' attributes, sending and receivi ng in teractive in formati on.Usually, the performa nee ofn etwork tran siti on is optimized through con diti ons updati ng and routi ng. Thein formati on excha nge ofhardware system com mon ly uses the custom wayof sending and receivi ng, whichis a pe

41、riodicaltran smissi on and fixed structure. The both possess differe nt protocols and themecha nism of in formatio nexcha nge. Therefore, in terface devices are required to complete the process ing of data conversion, to sendthe status of physical device and the real-time simulati on data to subsyst

42、ems ofman ageme nt and con trol,and to tran sfer the simulatio n con trol comma nds into the con trol in strume nt of the hardware mean while.(2) Functions for coord in ati on and man ageme nt of the simulati on time: the physical hardware system isphysical simulation time increasing, and each compo

43、nent in the simulation systemin creases its time by itsmeans, while the time is not con trollable and irreversible. RTI man ages the time of every member in HLAcen tralized to en sure the event' s logic correct ion at federatievel. I n the case ofhardware in HLAsimulation loop, the time uniform

44、is needed among HLA system time and federate members within depe ndent time promotio n. In other words, the events triggered by hardware system should be en sured tobe triggered to correct place on the timeline of a member of HLA Federation, and the events for a memberof HLA federati on is en sured

45、to correct place on the physics timeli ne of hardware system. Xue She ng et al. / Procedia En gi neeri ng 31 (2012) 801-806 805SOC RS232 UART In terface Unit Other systemPhysical device data sampleData conversionData distributio n man ageme ntTime man ageme ntEventman ageme ntFPGAMan ageme ntFig. 2.

46、 Block scheme of in terface un it4. Simulation and verificationTak ing adva ntage of prese nted semi-physical simulatio n system of micro-satellitebased on HLA, tak ingcerta in satellite model' s parameters as in put con diti ons, an orbital period of thesemi-physical simulatio nhas bee n comple

47、ted. The simulati on results are show n in Figure 3. Figure 3(a)shows the executio n resultsof status display federate in the micro-satellite semi-physical simulatio n using STK display program. Figure3(b) shows the result data of flywheel model in the dynamic federation and the speed and con trol m

48、ome ntcurve of history data. The curves will be updated real-timely during the simulation.Con trol mome ntFig. 3. (a) status of micro-satellite;(b) curves offlywheel speed, the con trol torque and power5. Con clusi onAccord ing to the real requireme nts of a micro-satellite, the hardwire-i n-loop simulati on system desig ningbased on HLA i