Civil Air Transport: a Fresh Look at Power-By-Wire and Fly-By-Light

1 NASA Technical Memorandum 102574

1 ....Civil Air_Transport: A Fresh Look at Power-by-Wire and Fly-by-Light

Gale R. Sundberg Lewis Research Center Cleveland, Ohio

Prepared for the National Aerospace and Electronics Conference (NAECON) sponsored by the institute for_jectrical and Electronics Engineers Dayton, Ohio, May 21-25, 1990

N90-ZI283 _= (NA_A-TM-]O2b7'+) CIVIL ATk TRANSPGqT: A FoESH L_,,OK AT POWFE-_,Y-WIRE AND rLY-,_ -LIGHT (NASA) 6 p CqCt. 09C uncl dS G3133 0277356 i _ _ _ _l _ ",m _ CIVIL AIR TRANSPORT: A FRESH LOOK AT POWER-BY-WIRE AND FLY-BY-LIGHT

Gale R. Sundberg National Aeronautics and Space Administration Lewis Research Center Cleveland, Ohlo 44135

Abstract the NASA Lewis study. The single electrlcal power system provides hlgher component ut111zatlon wlth slgnlfl- Power-by-wlre (PBW) Is a key element under sub- cant reductions in parts count, weight, failure modes, sonic transport flight systems technology wlth poten- and cost of ownership. tlal savings of over I0 percent In gross take off weight and In fuel consumption compared to today's The PBW technology el_mlnates the need for transport aircraft, The PBW technology substitutes 11c actuatlon and for englne bleed air to supply hydraucabin electrical actuation In place of centralized hydraul- comfort and anti-Iclng. It enables Integral starter/ Its, uses internal starter-motor/generators and ellml- generators for engine startlng and power generatlon to nates the need for variable englne bleed air to supply be used wlth advanced energy-efflclent engines without cabin comfort. gearboxes. These changes significantly Improve rue! efflclency and reduce alrcraft weight. Improved safety The application of advanced fiber optics to the and dispatch rellab111ty comblned wlth lower malnte- cf_ ! electrical power system controls, to bulIt-in-test nance and direct operating costs are additional tangl- L#J (BITE) equipment, and to fly-by-llght (FBL) flight con- ble benefits. trols provides addltlonal benefits In llghtnlng and hlgh energy radio frequency (HERr) immunity over exist- According to the study, e11mlnatlng the englne Ing mechanical or even fly-by-wire controls. Thls paper bleed for powerlng the envlronmental control system wlll review the program plan and glve a snapshot of the (ECS) and for anti-lclng provided the largest single key technologies and their benefits to a11 future alr- fuel savlngs of any proposed change. An electrlc motor craft - civil and military. driven ECS wlth electric Impulse driven de-icers are the proposed replacements. Introductlon Subsequent to the NASA Lewis study, addltlonal NASA In response to a directive from the U.S. Sen- technologies have emerged. The app11catlon of advanced ate has developed a multlyear technology development flber optics to the electrlcal power system controls, and validation plan that wlll help the United States to bullt-ln-test (BITE) equipment, and to fly-by-llght retaln Its leadershlp In aeronautics research and tech- (FBL) flight controls provides additional benefits In nology and compete In the international marketplace for 11ghtnlng and hlgh energy radio frequency (HERr) Immu- future clvil aircraft. One of the key elements under nlty over existing mechanical or even fly-by-wlre subsonic transport f11ght systems technology Is power- controls. by-wlre (PBW) wlth potential savings of over I0 percent In gross take-off-weight (GTOW) and fuel consumption This paper will review the program plan and take a compared to today's alrcraft (Ref. I). Fly-by-llght fresh look at some of the key technologles and their (FBL), whlch Is the replacement of electronic data beneflts to all future aircraft - civilian and military. transmission, mechanical control linkages, and elec- Figure I shows the payoffs and the major tasks planned tronic sensors wlth optical components and subsystems, for the PBW element. Figure 2 summarizes the prlmary Is another key element. elements of the FBL/PBW 5-yr program plan under the ClvlI Transport Inltlatlve. In the NASA Lewls Research Center study reported in Ref. I the stated benefits are shown to be possible The Electrical Powerp]ant | through the integration of an advanced secondary electrical power system Into a civil transport aircraft The heart of the electrical power system is a uslng a Boeing 767 as a baseline. While the particu- multlredundant, fau]t tolerant, microprocessor con- lar benefits may depend on aircraft slze and type, trolled, power management and dlstrlbutlon (PMAD) sys- engines, and specific electrical and flight control tem. It incorporates bidirectional Inverters driven systems, the range of improvements Is consistent with through a hlgh frequency, resonant utlIlty bus connected available advanced technologies. to internal starter-n_)tor/generators, thereby ellmlnat- Ing gearboxes and the need for separate APU's and engine The primary weight reduction occurred In the sec- starters. The hlgh frequency utlllty bus permits all ondary power system when the baseline hydraulic, pneu- the advantages of ac for stability, fault clearing, dlf- matic and electrlcal subsystems were replaced wlth a ferentlal monltorlng and control, as well as slgnlficant slngle, advanced high frequency, slnusoldal power man- crew/technlclan safety because of Its low energy per agement and distribution (PMAD) system wlth controlled pulse nature and ease of ground fault Interruption. energy flow and load management. An advanced fly-by- Figure 3 shows a typical utlIlty bus architecture for an wlre f11ght control system using electrlcal actuators ac PMAD system using advanced electronic switching for and advanced low fixed bleed hlgh bypass ratio engines power conditioning, control, dlstrlbutlon, protection contribute the remaining major advantages according to and a fault tolerant architecture (Ref. I). ThecharacteristicsoFtheadvancedPMAD system Pushing the Inte111gence down to the power switch and provlde the conduit to the benefits For PBW In civil circuit level enables easy verIflcatlon, validatlon, transport and perhaps certain military aircraft. The status, and malntalnablllty. It provides step-by-step resonant, high Frequency (>]0 kHz) ]Ink drive enables transltlons from manual to autonomous controls. Inte- either muItiphase low frequency ac sources or dc sources grated health monltorlng, Inciplent Fault prediction and to operate at their optimum voltage and Frequency at the a controlled evolution of power and avlonlc systems are Input. Since the main Inverters switch at the zero readily accommodated wlth each node communicating wlth crossing of either current or voltage, they mlnlmlze other nodes vla simple, common words. Thls enables dls- power losses, component stress, EMI/EMC and the need For tributed Intelllgence For Fault containment, Fault tol- heavy, bulky filters. The hlgh Frequency bldirectlona] erance, and autonomous control without massive software conversion and synthesis slgnIFIcantly reduces the slze Investments. and mass of the electronics components, controls and systematlcs. Electro-optlcal Controls

The key beneflt, however, comes in De ablllty to The Fly-by-llght (FBL) controls are proposed as a drive all kinds of motors (Including rugged Induction replacement of electrical data transmission, mechanical motors wlth high temperature capability) In either control linkages and electronic sensors wlth optical direction with Independent control of torque, speed and components and subsystems_ They circumvent electromag- maximized, efficient operation over the entire speed netic Interference (EMI) concerns In applying dlgltal range. In effect, all load control including variable controls by providing lifetime immunity to signal EMI speed motor drive is accomplished by sorting and steer- without need for shielding. The FBL technology will Ing the hlgh frequency slnusoldal pulses to the appro- demonstrate optical sensors and Interfaces wlth Improved priate power switch, motor winding or energy storage lightning and HERF Immunlty. element. Voltage regulation, power quallty and energy flow are determined and managed at all tlmes and within The FBL program wlll identify, develop, and evalu- specified limits. Multiple levels of redundancy are ate an optical sensor suite. The sensors will be easily accommodated In the system, prov_dlng fault Integrated Into Innovatlve electro-optlcal based Fault- containment, fault recovery, and maximized end-to-end tolerant archltectures using optical networks and efficlency. multlplexer/demultlplexer techniques. Performance and reliability assessments of the fault tolerant processors Electrical Actuatlon and architectures will provide a basis For developlng hardware and software For fllght test and Inservlce Existing electrical actuation technology in the evaluation. 5- to 50-hp range will be adapted to the flight control and other actuation requirements on an aircraft. Proto- Several ongoing actlvlties wi11 feed technology type electrical actuators operating from the distributed Into the FBL program: the Fiber optical control system power bus will be built and demonstrated In a full integration (FOCSI) program, the optical propulsion avlonIcs control environment. management Interface system being designed Into the advanced transport operatlng system aircraft, and a The electric actuators would replace hydraulic f|ber optical transmltter/recelver with adc 4-GHz band- actuators, servovalves, and mechanical control linkages. width. An extensive data base and experimental Investl- An advanced electrical actuation system Includes elec- gation of 11ghtnlng effects on digital electronics will tromechanlcal and/or electrohydraullc actuators, load serve as a baseline For assessing FBL enhancements to receivers, redundant digital data buses, and remote ter- the fllght control system. minals. Electrical actuators perform the same functions as hydraulic actuators with lower welght, hlgher effl- Summar Z ciency and without slzlng restrictions. The goal of the FBL/PBN program is to accomplish The dlgltal data bus and electro-optlcal sensors credible flight tests and demonstration of Full author- and controls promise to be a much lighter welght, more Ity, all dlgltal FBL/PBN transport alrcraft systems. fellable and EMI Immune approach than fly-by-wlre or Performance will be evaluated In the stress of flight mechanical controls. Also, many functions prevlously environments. The program will use the NASA advanced done wlth hardware can now be done with software. Thls transport operating system aircraft. Using parallel may Include such functlons as control surface damping operation of experimental equipment on the basic alr- and trlm. craft will maximize Flight test safety.

Status and Health The f11ght tests will be designed to verify and evaluate the Integrated system. FAA participation and MIcrochlp level BITE w11l be built Into the hard- coordination wlll be Integral to developing a prototype ware to provide a "F1ngerprlnt", which may include com- certification model. ponent characterlstIcs, test InFormatlon and valldatlon parameters. Such smart BITE chips could provide health Reference self-testlng for pre-FIIght checkout, For In-flight status and For malntenance assistance and records. I. Hoffman, A.C. et a1., Advanced Secondary Power System For Transport Alrcraft, NASA TP-2463; May The keys to autonomous, growable power and control 1985. systems are simple, smart, repllcatlve logic structures. POWER-BY-WIRE TECHNOLOGY

HEREIS WHAT WE PLANTO DO

DEMONSTRATE FAULT TOLERANT ELECTRICAL POWER SYSTEM

• ELIMINATE CATASTROPHIC POWER FAILURES

• SAFE FOR PASSENGERS/CREW USEELECTRICACTUATIONAND ENVIRONMENTAL CONTROLSYSTEM;VARIABLESPEEDPUMPS • IMMUNE TO LIGHTNING, HERF • OPERABILITY

• MAINTAINABILITY

VALIDATELeRC1985STUDY USEEXISTINGE3 ENGINETECHNOLOGY PROVIDEBUILT-INTEST(BITE) BOEING767 • ELIMINATESBLEEDPENALTY PBW SAVES • AUTOCHECK-OUT 10%NC WEIGHT • INCORPORATESINTEGRAL • SMARTEQUIPMENT& CABLE 10%FUELUSAGE STARTER/GENERATORS GRSgO-O01 11

FIGURE 1. - RAJORTASKSAND 8ENEFtTS OF POHER-BY-gIRE TECHNOLOGY.

r FAULT-TOLERANT ELECTRO-OPTIC _ ARCHITECTURE DESIGN & SENSOR INTEGRATION OPT1CA ENC, INE & AIRF'P,A J_ SENSORLS f INTEGRATED SYSTEM VERIRCATION

OPTICAL SENSOR EMI ENV1RONMEN'T J DEVELOPMENT & EVALUATION it_.m"z,m_.HEt_ I

[ PRESSU,RE]

f_WER-Byo_RE SYSTE_ J-_-ql -_,,= II _°s

DEVELOPMENT k_ J ALLi.c-LECTRtC ARCt-ff_CTURE

fFLIGHT EVALUATION 1

FIGURE 2. - ELEI_NTS OF FLY-BY-L]GHT/POk'ER-BY-WIRE PROGRAR. Left I 60-Hzservicegroundpower + engine

I conveBi-directionalrte r " I ! converterBi-directional Bi-directionalconverter I IBi-directionalconverter I _ turbineRam air I

Dual high-voltage, high- frequency buses

Bi-directional conveMer with converter with 1 _L I cBi-directionalha rge cont rot charge control _z

Uninterrupted 'I Hot dc batter,/bus I computer bus

-IBcI Leftdcbus I I Rightbatterybus I8cI--

/ _-[EF controller/motor BC l ECSI air-conditioner I ] EE]- controller/motor

¢ I LeftflightcontrolbusIscI E_- IBcI Rightf,ightcontrolbusI

¢ [i Leftmainbus IBcI 18cI ,_h,ma,nbo,,!

400-Hz s},nthesizer 400-Hz synthesizer , 1 I .... ! I =o-.z,.,II_=-vo._e,u,] LLow-vmagebusJl 4{]O-Hzbus

I Left utility bus IBcl I IB_! ._.,o,,,,_b°.I

Highfrequencyt°ll400-Hz synthesizer Transformer I 4]O-Hz synthesizer , I I L_-_o,o_e_o,I i _-"z_,',I El I Left galley bus IBCI 1so Rightga,,eybus I

BC bus controller BI bus isolator ECS environmental control system

FIGURE 3. - ADVANCED POWER D[STRIBLITIONSYSTEM. National Aeronautics and Report Documentation Page Space Administration t. Report No, 2. Government Accession No. 3. Recipient's Catalog No. NASA TM-102574

4. Title and Subtitle 5. Report Date

Civil Air Transport: A Fresh Look at Power-by-Wire and Fly-by-Light

6. Performing Organization Code

7. Author(s) 8. Performing Organization Report No.

Gale R. Sundberg E-5402

10. Work Unit No.

506-41-41 9. Performing Organization Name and Address 11. Contract or Grant No. National Aeronautics and Space Administration Lewis Research Center

Cleveland, Ohio 44135-3191 13. Type of Report and Period Covered Technical Memorandum 12 Sponsoring Agency Name and Address

National Aeronautics and Space Administration 14. Sponsoring Agency Code Washington, D.C. 20546-0001

15. Supplementary Notes

Prepared for the National Aerospace and Electronics Conference (NAECON) sponsored by the Institute of Electrical and Electronics Engineers, Dayton, Ohio, May 21-25, 1990.

!16. Abstract

Power-by-wire (PBW) is a key element under subsonic transport flight systems technology with potential savings of over 107_ercent in gross take-off-weight and in fuel consumption compared to today's transport aircraft. The PBW technology substitutes electrical actuation in place of centralized hydraulics, uses internal starter- motor/generators and eliminates the need for variable engine bleed air to supply cabin comfort. The application of advanced fiber optics to the electrical power system controls, to built-in-test (BITE) equipment, and to fly-by- light (FBL) flight controls provides additional benefits in lightning and high energy radio frequency (HERF)i_-.- =:-- immunity over existing mechanical or even fly-by-wire controls. This paper will review the program plan "a'nd give a snapshot of the key technologies and their benefits to all future aircraft--civil and military. \

17. Key Words (Suggested by Author(s)) 18. Distribution Statement

Electrical actuators; Electrical power systems; Unclassified- Unlimited Secondary power; Power-by-wire; Civil transport Subject Category 33

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of pages 22. Price* Unclassified Unclassified 6 A02

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