INTEGRATED MODULAR MEASUREMENT SYSTEM FOR IN-FLIGHT TESTS

Diagnostyka, Vol. 15, No. 1 (2014) 53 INTEGRATED MODULAR MEASUREMENT SYSTEM FOR IN-FLIGHT TESTS Grzgorz KOPECKI, Pawł RZUCIDŁO Politchnika Rzszowska, Wydział Budowy Maszyn i Lotnictwa, Katdra Awioniki i Strowania 35-959 Rzszów, al. Powstańców Warszawy 12, gkopcki@prz.du.pl, pawlrz@prz.du.pl Summary During th dvlopmnt of th aircraft structur, tst flights ar indispnsibl. In som xprimnts additional snsors ar mountd, which oftn lads to crtain tchnical problm. In particular, changs of th structur ar ncssary and additional costs ar gnratd. Thrfor, advancd masurmnt mthods nabling an analysis of svral paramtrs without adding spcial snsors ar dvlopd. On of th projcts focusd on problms of masurmnt during th flight is th AIM2 projct in th frams of FP7. During rsarch mobil optical masurmnt systms and application ruls ar dvlopd As dscribd in rfrncs [1, 2], th AIM projct - Advancd In-flight Masurmnt Tchniqus focusd on th application of modrn optical masurmnt tchniqus in industrial wind tunnls for th purpos of flight tsting. Possibilitis to masur wing and rotor dformation, surfac prssur distribution, hat distribution and flow vlocity filds in a non-intrusiv way and with a minimal snsor stup wr prsntd in th AIM projct. Also, th most important challngs connctd with industrial implmntation of mthods dmonstratd in th AIM projct wr takn into considration. Th rsarch is bing continud in AIM² projct. AIM2 aims at th dvlopmnt of masurmnt mthods for asy and typical applications to inflight tsting with industrial rquirmnts. In ordr to tst th optical masurmnt mthods, additional flight data ar rquird. Th data rquird ar angular rats in th body fram, Eulr angls, acclrations, IAS, TAS, altitud. This articl dscribs a systm which is usd in th projct for additional data masurmnts. Th whol systm will b mountd on th board of th PW-6 glidr. Kywords: data acquisition, monitoring, flight tsts. ZINTEGROWANY MODUŁOWY SYSTEM POMIAROWY DLA BADAŃ W LOCIE Strszczni Podczas prac projktowo-rozwojowych powiązanych z projktowanim konstrukcji lotniczych, nizbędn jst wykonani prób w loci. Niktór tsty wymagają montażu dodatkowych czujników, co często jst powodm różngo typu problmów tchnicznych. Często w takich sytuacjach nizbędn są zmiany w strukturz konstrukcji, co gnruj dodatkow koszty. Dlatgo rozwijan są mtody umożliwiając analizę różngo typu paramtrów, któr ni wymagają montażu dodatkowych snsorów. Jdnym z projktów, który koncntruj się na problmatyc pomiarów podczas prób w loci jst projkt AIM2, ralizowany w ramach 7 Programu Ramowgo Unii Europjskij. Podczas badań, rozwijan są mobiln optyczn systmy pomiarow oraz ich aplikacj. Jak opisuj bibliografia [1, 2], projkt AIM - Advancd In-flight Masurmnt Tchniqus koncntrował się na zastosowaniu w badaniach w loci współczsnych tchnik pomiarowych, któr są stosowan podczas badań w tunlach arodynamicznych. W projkci AIM, przy minimalnym zstawi czujników oraz bz ingrncji w strukturę konstrukcji, zostały zaprzntowan możliwości pomiaru dformacji skrzydła oraz wirnika, rozkładu ciśniń na powirzchni, rozkładu cipła oraz prędkości przpływu. W ramach projktu AIM przanalizowano równiż najważnijsz wyzwania związan z implmntacją przmysłową dmonstrowanych mtod. Badania są kontynuowan w ramach projktu AIM². Projkt tn ma na clu rozwój mtod pomiarowych w clu ułatwinia ich stosowania podczas badań w loci, zgodni z wymaganiami przmysłowymi. W clu tstów mtod optycznych, wymagan są dodatkow dan pomiarow: prędkości kątow w układzi współrzędnych związanym z samolotm, kąty Eulra, przyspisznia, prędkości lotu IAS oraz TAS, wysokość. Ninijszy artykuł opisuj systm, który użyty zostawł w projkci dla clów pomiaru dodatkowych danych. Systm jst wykorzystywany podczas prób na pokładzi szybowca PW-6. Słowa kluczow: akwizycja danych, monitorowani, próby w loci.

54 Diagnostyka, Vol. 15, No. 1 (2014) 1. MEASUREMENT SYSTEM - GENERAL IDEA Th gnral schm of th masurmnt systm is prsntd in figur 1. Th systm masurs such paramtrs as: - attitud angls (pitch, roll, yaw), - angular rats in body fram (p, q, r), - acclrations in body fram (ax, ay, az), - static and dynamic prssur, - angl of attack and slid-slip angl, - GPS paramtrs (latitud, longitud, track angl, hight), - tim data. All units ar connctd to th CAN data bus. Data ar rgistrd with th us of spcializd softwar on th board of a PC computr, which is connctd to th CAN bus with th us of a CAN- USB intrfac. Th systm contains an intgratd AHRS+GPS+ADC modul, A/D and a digital input. To th intgratd AHRS+GPS+ADC modul, and two A/D inputs an arodynamic prob is connctd. Th arodynamic prob nabls th masurmnt of th total and dynamic prssur, th slid-slip angl and th angl of attack. 2. INTEGRATED AHRS+GPS+ADC Th unit masurs angular rats, acclrations, static and dynamic prssurs, GPS data. For prssurs, snsors MPXV5010DP and MPXAZ6114AP wr usd [3, 14]. For angular rats L3G4200D, for acclration LSM303DLHC wr applid [4, 5]. Additionally, th implmntd softwar calculats attitud angls (pitch, roll, yaw). Th calculation algorithm is basd on quatrnion algbra. Dtails of attitud calculation with th us of algbra is dscribd.g. in bibliography [8, 10, 14]. Quatrnion is a numbr systm that xtnds th complx numbrs. It can b prsntd as four dimnsional vctor. Masuring angular rats in th aircraft body fram, quatrnion drivativs can b calculatd: whr: 0 1 ε = - quatrnion 2 3 L Ω 1 0 = 3 2 K p = q r 0 1 1 ε& = L Ω (1) 2 2 3 3 2 1 0 Nxt, from quatrnion, attitud and hading is obtaind: 2( tan Φ = (2) 2 0 0 1 + 32 ) 2 2 2 1 2 + 3 sin Θ = 2( 02 31 ) (3) K Fig. 1. Gnral schm of th systm

DIAGNOSTYKA, Vol. 15, No. 1 (2014) 55 2( tan Ψ = (4) 2 0 0 3 + 1 2) 2 2 2 1 2 + 3 CAN bus. Th data ar rgistrd, and all arodynamic data can b calculatd offlin. Th advantag of applid algorithm is th possibility of masurmnt of Eulr angls in all aircraft configuration. Additionally, numrical rrors can b corrctd with th us of quatrnion norm, as dscribd in [8]. Quatrnion norm quals always 1: 2 2 3 2 0 1 2 3 = E = + + + 1 (5) If numrical rrors appar, th quatrnion norm E obtains valus diffrnt from 1. Exmplary corrction quation is prsntd blow: Fig. 2. Intgratd AHRS+GPS+ADC modul 0 0 1 1 = 2 2 3 3 1 E (6) (11) Corrction of gyroscops masurmnt rrors is basd on complmntary filtring. During turning, gravity corrction in th roll channl is switchd off. Du to aircraft dynamic proprtis, corrction basd on gravity angls calculatd from acclrations cannot b switchd on continuously. In th solution proposd, corrction is switchd off during turning in roll channl. All masurmnt data ar rgistrd, which mans that in th cas of problms attitud and spds calculation can b additionally ralizd offlin. Th modul snds attitud and hading angls, as wll as all masurmnts to th can bus. All data ar rgistrd on a PC computr. All snsors wr calibratd. For xampl, th static prssur snsor was calibratd in rang 450 1020 hpa. Taking into considration prssur distribution in th function of hight, masuring points in th rang 900-1020 hpa wr takn with a stp 10 hpa. Nxt, masuring points in rang 800-900 ach 20 hpa wr takn, and masuring points in th rang 450 800 hpa ach 50 hpa. Figur 3 shows dpndnc btwn th prssur and snsor raw output. Dynamic prssur is rquird for aircraft spd calculation (IAS, TAS, CAS). For snsor scaling, prssur points charactristic for PW-6 instrumnt airspd (IAS) wr chosn. Prssurs usd for scaling wr rprsntativ for IAS from 50 km/h to 220 km/h, with a stp of 10 km/h. Figur 4 shows th rsults of calibration. It was assumd that th static charactristic of applid snsors is linar for both th static and dynamic prssur. Scaling cofficints wr calculatd with th us of last squars mthod. Th systm snds static and dynamic prssur to th Fig. 3. Static charactristic of raw data for static prssur Fig. 4. Static charactristic of raw data for dynamic prssur snsor 3. A/D AND DIGITAL INPUTS UNIT Figur 5 shows A/D and a digital inputs unit. It is usd for th masurmnt of th angl of attack and slid-slip angls. Th unit masurs analog inputs and snds thm to th CAN bus. Nxt, it transfrs th information masurd from th angl of attack and slid-slip angl probs to th CAN bus. Valus from potntiomtrs ar snt to th CAN bus as raw data, and consquntly, offlin analysis is rquird.

56 DIAGNOSTYKA, Vol. 15, No. 1 (2014) 4. PC DATA RECORDING SYSTEM Th systm consists of a PC computr with a CAN- BUS intrfac and ncssary softwar. Th most important unit is th CAN-monitor systm [11]. Figur 6 shows an xmplary window of th systm. Each fram is rcordd in th fil, with information about th CAN-USB systm tim. Th systm nabls visualization of all data snt in th CANArospac standard. Th opn CANArospac protocol is dscribd in [12]. In th rcording and visualization systm, ach masurmnt has a sparat CAN fram with a uniqu, normalizd idntifir. This solution offrs th possibility of data synchronization. Aftr vry in-flight xprimnt, data ar dcodd with th us of dcoding softwar. Figur 7 shows an xmplary window of th data dcoding softwar. For data dcoding, all idntifirs must b introducd to th ID windows. Figur 8 shows an xmplary viw of dcodd data. Each masurmnt is in a distinct column. Th first column is always tim (sconds). Th first row givs information about data in ach column (uniqu information in CAN arospac protocol). Fig. 5. A/D and digital inputs unit Fig. 6. Exmplary window of CAN monitor systm Fig. 7. Exmplary fil with dcodd data

DIAGNOSTYKA, Vol. 15, No. 1 (2014) 57 Figur 8. Data dcoding softwar. 5. FLIGHT TESTS Th complt intgratd modular masurmnt systm was installd on th board of a PW-6U xprimntal glidr (Fig. 9 and 10). Static prssur, dynamic prssur, angl of attack (AOA) and angl of sidslip (AOS) probs wr mountd on th xtnsion arm, on th top of glidr s fuslag (Fig. 11). Th PW-6U, quippd with th xprimntal systm, was ground towd in th ara of th EPRJ airport. Figur 12 prsnts ground spd (GS) obtaind from a GPS rcivr. Th glidr rachd GS=45 km/h without any significant chang in altitud (Fig. 13). Glidr did not lift off in th fact bcaus this xprimnt was plannd as an xtndd ground tst. Plot of dynamic prssur, connctd with airspd, is prsntd in figur 14. Cours of runway (270 dg) was maintaind prcisly (Fig. 15) during th whol tst. Fig. 10. Intgratd AHRS+ADC+GPS mountd on th board of PW-6U glidr Fig. 11. Arodynamic prob (with rd plugs) Fig. 9. Gnral viw of PW-6U glidr prpard for AIM xprimnts Fig. 12. Ground spd rcordd during towing with a car (EPRJ airport, runway 27, Aug 14, 2013)

58 DIAGNOSTYKA, Vol. 15, No. 1 (2014) Fig. 13. GPS altitud rcordd during towing with a car Fig. 16. Pitch and roll rlatd to fig. 12-15 Fig. 14. Dynamic prssur, plot rlatd to figur 11 Fig. 17. Plot of angular rat p Fig. 15. GPS tru track rlatd to figur 12-14 Fig. 16 prsnts rcordd roll and pitch. Just bfor towing, th longitudinal as wll as th latral axis of th glidr wr situatd narly horizontally. Th pitch angl was incrasd initially, but at th nd of towing its valu was dcrasd and, aftr braking, it stabilizd narly at zro. Aftr braking th bank angl rachd 10 dgrs bcaus of lowring of th glidr s right wing. Raw data obtaind from MEMS (Micro Elctro-Mchanical Systms) gyroscops ar prsntd in Figurs 17-19. Angular rat in th latral motion was faturd by maximum rang of variability (Fig. 17) and it rachd ±20 dg/s during towing. Angular rat did not xcd ±10 dg/s longitudinally (figur 18) and ±5 dg/s in th yaw axis (figur 19). Fig. 18. Plot of angular rat q Fig. 19. Plot of angular rat r

DIAGNOSTYKA, Vol. 15, No. 1 (2014) 59 BIBLIOGRAPHY Fig. 20. Acclrations rats rlatd to figur 11 Maximal variablity of rcordd accllrations (±1 m/s 2 ) was rcordd in axis z (vrtically). Othr accllrations rmain gnrally in rang ±0.5 m/s 2 (Fig. 20). Applid AOA and AOS probs can work in th rang of ±30 dg, howvr thir indications can b intrprtd aftr xcding about 35 km/h airspd. This condition was obtaind btwn 2940-2970 s (Fig. 21). In this priod, AOA is ngativ or approachs zro bcaus, during towing with a car, th pilot was not allowd to lift th glidr off th ground Bcaus of sid wind compnsation (wind from dirction 180 dg), AOS rachd 12 dg and was gnrally positiv. Fig. 21. Angl of attack and angl of sidslip rlatd to figur 11 5. CONCLUSIONS As prsntd in th articl, th systm rgistrs th most important aronautical data. It is univrsal and opn for dvlopmnt. Additional units can b addd. Th only rquirmnt is communication with th us of th CAN data bus with a CAN arospac protocol. Th unit was tstd prliminarily during th flight. Data masurd via an analogical masurmnt unit with th sam snsors wr usd for an autonomous flight of a small UAV [6, 7, 9, 15]. Th masurmnt systm aids dvlopmnt of optical mthods for in flight tsting. [1] Advancd in-flight tsting for bttr aircraft dsign, Rsarch.u, Rsults Magazin, No 20, March 2013. [2] AIM 2 official wbsit, http://aim2.dlr.d, (23.06.2013). [3] Datasht: Frscal Smiconductor MPX5010 Rv 12, 09/2009. [4] Datasht: L3G4200D MEMS motion snsor: ultra-stabl thr-axis digital output gyroscop. [5] Datasht: LSM303DLHC Ultra compact high prformanc -compass 3D acclromtr and 3D magntomtr modul. [6] Gosiwski Z., Kulsza Z. [rd], Mchatronic Systms and Matrials IV, Kopcki G., Tomczyk A., Rzucidło P., Algorithms of Masurmnt Systm for a Micro UAV, Solid Stat Phnomna, Vol. 198, Trans Tch Publications Inc., Zurich 2013, pp. 165-170. [7] Gosiwski Z., Kulsza Z. [rd], Mchatronic Systms and Matrials IV, Rzucidło P., Unmannd Air Vhicl Rsarch Simulator - Prototyping and Tsting of Control and Navigation Systms, Solid Stat Phnomna, Vol. 198, Trans Tch Publications Inc., Zurich 2013, pp. 266-274. [8] Gosiwski Z., Ortyl A.: Algorytmy inrcjalngo bzkardanowgo systmu orintacji i położnia obiktu o ruchu przstrznnym. Sris: Bibliotka Naukowa Instytutu Lotnictwa, Warszawa 1999. [9] Grzybowski P., Rzucidło P., Systm for tsting and simulation of Unmannd Arial Vhicl and its componnts, Canada's Prmir Unmannd Vhicls Systms Confrnc, Novmbr 6th-9th, Ottawa, Ontario, 2012. [10] Kopcki G., Rogalski T.: Aircraft Attitud Calculation With th Us of Arodynamic Flight Data as Corrction Signals, AESCTE2979, Arospac Scinc and Tchnology 32 (2014), pp. 267-273 DOI: 10.1016/j.ast.2013.10.009. [11] Kopcki G., Rzucidło P.: Problms of Monitoring in th Fly-by-Wir Systm for Small Aircraft, Chaptr DOI: 10.2514/6.2006-6340 Publication Dat: 21 August 2006-24 August 2006. [12] Michal Stock, Flight Systms: CAN Arospac: Intrfac spcification for airborn CAN applications, V 1.7, http://www.stockflightsystms.com/canarospa c.html [13] Mystkowski A., Robust Optimal Control of MAV Basd on Linar-Tim Varying Dcoupld Modl Dynamics, Mchatronic Systms and Matrials, IV Book Sris: Solid Stat Phnomna Volum: 198 Pags: 571-576. [14] Pacs P., Sipos M., Rinstin M., t al., Snsors of air data computrs - usability and nvironmntal ffcts, Intrnational Confrnc

60 DIAGNOSTYKA, Vol. 15, No. 1 (2014) on Military Tchnologis, Brno, May 05-06, 2009. [15] Szpunar R., Rzucidło P., Koncpcja wykorzystania aktywnj sici godzyjnj ASGEUPOS w układzi strowania i nawigacji latającj platformy bzzałogowj, Przgląd Elktrotchniczny, R. 88 NR 12a/2012, SIGMA-NOT, Warszawa 2012, str. 154-158. ACKNOWLEDGEMENTS Th prformd and prsntd study was part of th AIM2 projct foundd by th Europan Commission within th 7th framwork program (contract No. ACPO-GA-2010-266107) Dr inż. Pawł RZUCIDŁO jst pracownikim Katdry Awioniki i Strowania na Wydzial Budowy Maszyn i Lotnictwa Politchniki Rzszowskij. Jst autorm monografii Oscylacj indukowan przz pilota w układzi pośrdnigo strowania samolotm oraz współautorm monografii Systmy pośrdnigo strowania dla samolotów ogólngo przznacznia. Dr inż. Grzgorz KOPECKI jst pracownikim Katdry Awioniki i Strowania na Wydzial Budowy Maszyn i Lotnictwa Politchniki Rzszowskij. Jst autorm monografii Strowani samolotm w sytuacji nipłnj informacji pomiarowj. Zaintrsowania naukow: lotnicz systmy strowania.