CONTROL DJS'PLt'\Y................9 INFORMATION CENTER NO.Z

'9 W A PROTOTYPE PERIPHERAL VISION ARRFATTITUDE DISPLAY

WILLIAM R1. WILLIAMSON

TECHNICAL REPORT AFFDL-TR-66-91

OCTOBER 1966

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WRIGHT-PATTERSON AIR FORCE BASE, OHIO

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NOTICES

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Copies of this report should not be returned to the Research and Tech-

nology Division unless return is required by security considerations,contractual obligations, or notice on a specific document.

200 - December 1966 - C0192-13-252

AFFI)L-TR-56-91

A PROTOTYPE PERIPHERAL VISION AIRCRAFTATTITUDE DISPLAY

WILLIAM R. WILLIAMSON

Distribution of this d Jcum

AFFDL-TR-66-91

FOREWORD

This report was prepared by Link Division, General Precision, Inc. for the Air Force onContract Number AF 33(615)2895, Project 6 ,,, 1The Ar Forc ContrA-DIslay Program."for which Mr. John H. Kearns III served as Project Engineer. The effort was administratedunder the direction of the Flight Control Division, Air Force Flight Dynamics Laboratory,Wright-Patterson Air Force Base, as a part of Task Number 619004, "Control-DisplayEvaluation". Mr. Robert R. Davis served as Technical Monitor. The contractor's assignedjob number for this study is 64-132.

The System was designed and constructed by Mr. Wolfred Greenberg and Mr. H.G. Ledbetter.This report was prepared during April 1965 by Mr. W. R. Williamson, Senior Engineer,General Precision, Inc., Link Division.

This is one of a succession of reports presenting results achieved in a continuing heuristicinvestigation in the area of control-display being conducted under Project 6190.

Manuscript released by the author June 1966 for publication as an RTD Technical Report.

This technical report has been reviewed and is approved.

LOREN A. ANDERSON, Major, USAFChlef, Control Systems Research BranchFlight Control Division

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AFFDL-TR-66-91

ABSTRACT

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that he may maintain an awareness of his attitude through Peripheral Vision without thenecessity for looking directly at a specific instrument. The system does this by projectinga line of light on the aircraft instrument panel and moving it in a manner similar to the motionof the real horizon. A design criteria and a detailed engineering description of the workingmodel are also presented.

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AFFDL-Tl-66 -91

TABLE OF CONTENTS

SECTION PAGE

I INTRODUCTION 1

II TECHNICAL DESC IPTION 2

III DESIGN DETAILS 6

Pitch System 6

Roll System 6

Heading System 6

Optical System 6

IV SUMMARY AND CONCLUSION 9

Summary 9

Conclusion 9

V REFERENCES 10

V

AFFDL-TR-66-91

ILLUSTRATION6

FIGURE PAGE

1 Peripheral Vision Display Block Diagram 3

2 Heading and Roll Mechanisms 4

3 Side View of Projector Assembly 7

4 Top View of Projector Assembly 3

5 Pitch System Schematic 11

6 Roll System Schematic

AFFDL-TB-66-91

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Often during nstrument flight, the pilot sophisticated to determine the optimum lightmust look away from the Instrument panel for line dimensions. Finally, the motion cuesshort periods. Not infrequently the attitude were restricted to changes about the roll andof the aircraft changes gradually without the pitch axis with no provision for the changespilot's cgnizancc while bis attention is di- in yaw.verted. Under contract onditions, the pilot Encouraged by the feasibility demonstratedcan n-'rmally detect attitude changes through in the early effort, Control Systems Researchperipheral visin motion cues even if his Branch, Air Force Flight Dynamicsattentioa is directed into the cockpit. Laboratory, began the development work de-

Early in 1960, this Laboratory began its scribed in this Technical Report. The result

first effnrt to extend peripheral vision motion of this new work was a functional prototype

cues i n to instrument flight. A systom was Peripheral Vision Attitude Display. This dis-

designed and built which projects attitude in- play retained the pitch and roll presentations

formation in the form of a movable light line of the earlier system but added light line

on the aircraft istrument panel. The purpose modulation to provide yaw motion cues.

of the light line was to extend the horizon Because the Simulation Facility isline of the attitude director indicator (ADI). frequently visited by military and commercialThe movement of the light line in pitch and pilots of friendly nations, a good cross sectionroll was made to coincide with that of the of pilot opinion about the value of this typeADI horizon line. Although the feasibility of presentation was obtained informally. Initialusing a project light line to present breadboard exploratory simulation effortsperipheral vision motion cues was demon- produced encouraging results. Consequently,strated, this early system had three severe a fully functional prototype was built and in-shortcomings. First, the light source, a stalled in a simulator. This was the systemmercury vapor lamp, generated excessive used to obtain subjective reactions of pilotsheat. Second, the equipment, as originally concerning the desirability and requirementsconceived and built, was not sufficiently for such a device.

AFFDL-TR-66-91

SECTTON il

TECHNICAL DESCRIPTION

The optical portion of the Peripheral Vision The heading synchro-receiver is mountedDisplay was based upon a slide projectork-. directly on the roll gear and extends backThe parts from this kit, and a servo-motor- through a hole in the lens mounting disc.driver mirror assembly, comprise the light The synchro-receiver provides enoughtorquebeam projection and pitch motion portions of to drive the heading spoked wheel directlyth6 display. The rest of the system was without a servo-motor. No brush and ringdesigned at the Simulation Facility. assembly is needed since it is seldom

necessary to consider a roll requirementReferring to the Block Diagram, Figure 1; greater than 90 degrees either side of

the output of the light source is condensed center. Wiring to the heading synchro hasinto a beam which passes through a cylindrical enough flexibility (extra length) to permitlens forming a narrow line of light. This beam several continuous 360-degree roll-over ma-is further narrowed by passing it through a neuvers without winding up to the extent thatalit mask and another condensing lens. It then it applies a load to the mechanism. This is apasses through the focusing prolection lens to very unlikely occurrence in simulation equip-a mirror and is reflected onto the aircraft ment.instrument panel. The line is rolled about afixed point by rolling the cylindrical lens and The edge drive for the roll mechanism isslotted mask. Pitching motion is accom- provided by a synchro- receiver servo-motor.plished by rotating the mirror around an The gearing from the motor output shaft to theoffset axis. The modulated horizontal lines edge drive gear is a 4:1 btep down. The ratioare achieved by rotating a spoked wheel from the edge drive gear to the roll gear isthrough the light at its source. The spoked also 4:1 as is the ratio from the edge drivewheel drive mechanism "rides" o:. the rotat- shaft to the roll synchro gear. This resultsing cylindrical lens disc so that the rudulated in synchronus rotation of the roll gear andlines always appear to move along the pro- synchro gear. The servo amplifier for thejected light line regardless of its orientation, roll system is built into the Universal Flight

Trainer computer cabinet and consists of aThe light source and beam forming ap- d.c. operational amplifier, a generalpurpose

paratus is comprised of a 100-watt projec- 400 cps demodulator, a 3.5-watt magnetiction bulb, reflector, and two condensing amplifier, and a matching transformer.lenses, all from the projection kit.

The modulated light line is passed throughThe line forming cylindrical lens and a condensing lens and fast f/1.9 projection

slotted mask are mounted on an edge driven lens (both part of the slide projector kit) tounit consisting of a 4-in. gear and ring the servo driven mirror. The mirror unitassembly and an offset 4-in. disc, (Figure 2). consists of a servo motor which drives aThe lens is mounted on the disc and the mirror tilt platform through a precisionslotted mask is mounted on the gear. The worm and wheel gear assembly. The mirrorgear and ring are staked together, and the which is mounted approximately 4 feet fromcylindrical lens mounting disc is attached by the instrument panel, may be positionedfour bolted spacers, thus forming a rigid through an arc of approximately 45 degrees.unit. The device was first attempted with Such angular displacement is adequate forjust the gear and lens mounting disc. with normal pitch representation. The axis ofsmall free rotating gears instead of rollers rotation of the mirror is offset from the pointfor support. This resulted in an excessive of light line incidence. The purpose of thefriction load for the roll motor drive unit. offset is to reduce distortion when the lineisLater, when the ring and pulley support tilted in the roll plane. Thus, the focalrollers were added, satisfactory results were distances of the ends of the tilted tine are asachieved, equal as possible, consistent, with the

AFFDL-TR-66-91

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physical length of the projector. Ideally, the Flight Trainer, is scaled so that five degreesmirror would be an "infinite" distance from is approximately equal to three inches verti-the nrolectc r. cal movement of the light line. Power re-

quirements are 115 vac for the Display atThe mirror drive, also a synchro servo- 400 cps, 115 vac at 60 cps. and -28 vdc.

mechanism, accepts pitch information from Power requirements could be reduced some-the Universal Flight Trainer in 3-wire what since the 60-cycle power is used onlysynchro form and produces a single phase for the projection light bulb and the 400-cycleerror signal. A transistorized servo-ampli- power for the cooling fan and the servo control.fier is an integral part of the projector in the The -28 vdc is for the pitch servo amplifier.pitch system. Input requirements are for roll, pitch and

heading signsis. These three signals are inThe overall Peripheral Vision Display is 11.8 vac, 400 cps, 3-wire synchro form. Two

8 in. wide, 6-1/4 in. high, and 19 in. long. switches are used to turn the system on andIt projects a line approximately two feetwide off; one is for the projector, including headingonto a flat black surface up to fivefeet away. and roll, and one is for the pitch system,Pitch movement, as set up in the Universal which is external to the projector.

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AFFDL-TR-66-91

SECTION IHv~l ,1 UET A I,

PITCH SYSTEM roll optics disc mechanism (Figures 2 and 4).This servo motor has a gear head as an in-

The servo-motor-driven mirror assembly tegral attachment.unit (Figure 3) consists of a 400 cps servomotor, size 18,115-volt fixedphase, 115/57.5 A 400 cps, Torque receiver, size 10, singlevolt control phase, driving a mirror tilt phase 26 volt rotor, three-phase 11.8-voltplatform through a precision worm-and- stator, is used as the control transformer inwheel gear assembly. The wheel shaft is the roll servo loop. It accepts the 3-wire rollfitted with three adjustable cams which information f r o m the U ni v e r s a 1 Flightoperate limit switches. These were notused. Trainer and provides the error signal for the

roll optics mechanism (Figure 4).The optically flat mirror (Figure 3) is

3 in. wide, A-/4 in. high, and 3/8 in. thick. The servo amplifier is composed of spareIt may be positioned through an arc of ap- units existing in the Universal Flight Trainer;proximately 45 degrees. Overall dimensions a d.c. operational amplifier, a general pur-are 4-1/2 in. in width, 6 in. in length, and pose 400 cps demodulator (Reference 1), a6 in. in height when the mirror is at the 115-volt, 3.5-watt, 400 cps magnetic am-highest point. plifier, and a speaker matching transformer

for impedance match of the motor (Figure 4).A synchro transmitter, size 8, single phase

26-volt rotor, three phase 11.8-volt stator, HEADING SYSTEM400 cps, is used as a synchro control trans-former in the mirror-drive servo loop The heading system consists of a spoked(Figure 3). It accepts the three-wire pitch wheel (shown in Figure 2 and also laying oninformation from the Universal Flight top of black box in top view photo Figure 4.1Trainer. The trainer is a simplified aircraft driven by an Autosyn synchro receiver,simulator located in the Flight Dynamics Lab- 400 cps, 26-volt single phase, 11.8-voltoratory Simulation Facility. It is specifically 3-phase. There is no servomechanism; theintended for projects of this nature. The synchro receiver produces enough torque tosynchro transmitter develops an error signal drive the wheel as a function of the 3-wirefor the motor-driven mirror assembly. heading (or yaw) information from the Uni-

The transistorized servo amplifier, shown versal Flight Trainer.in Figure 1, was developed by the Link Group OPTICAL SYSTEMat the Flight Dynamics Laboratory (Reference2). The optics in the Peripheral Vision Display

(Figures 1 and 2) are composed of a SlideROLL SYSTEM Projector Kit and a cylinder lens. A complete

A 400 cps, servo motor, size 10, 115-volt set of instructions for building the projectorfixed phase, 60-volt control phase, drives the accompanies the kit.

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AFFDL-TR-66-91

SECTION IV

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SUMMARY Optical distortion is low. 'The disnlay wasdemonstrated, on an informal bas. - to ap-

During instrument flight conditions, an proximately fifty people over a period of aaircraft's attitude can gradually change be- few months. Based on the work conducted oncause the pilot's attention is diverted to the Peripheral Vision Display, and the corn-operate a radio or navigation equipment. ments received, the following conclusionsUnder these conditions, the pilot, throughhis were made:peripheral vision, is aware of these attitudechanges even though his attention is directed 1. Senior individuals in airline companiesaway from the flight instruments. The concept indicated that such a device is needed, and thatof this project was to develop a prototype this approach to presenting information woulddevice whichwouldpresentvisualinformation be a real aid to pilots.to the pilot and make use of his peripheralvision. 2. The curved cowling in modern cockpit

Initial breadboard exploratory efforts were configurations no longer adequate for pilots

conducted to project a line of lightacrossthe to line up the horizon with the top of the

instrument panel of a simulator. The light instrument panel.

beam moved in the pitch and roll axis and 3. An artificial horizon line projected onwas modulated to give the illusion of heading the instrument panel reduces pilot fatigue, byor yaw motion. A prototype instrument was reducing the quantitative instrument readingsdeveloped which utilized a slide projection that are required.kit for the optical portion of the display. Alight source was condensed into a beam and 4. Pitch and roll changes are shownpassed through a cylindrical lens. The light immediately, even though the pilot' s attentionbeam was reflected from a mirror assembly is directed away from the flight instruments.on to the instrument panel. Pitch and rollmovement was accomplished by rotating the 5. A light line provides the transition frommirror assembly for the pitch axis, and the instruments to the outside world, underrotating the cylindrical lens in the roll axis. contact conditions. This transition has longThe modulated horizontal lines were achieved been lost due to the present design of cockpitby rotating a spoked wheel through the light windows.line.

CONCLUSION 6. The pitch display unit is permanentlyattached to the Universal Flight Simulator.

The first operational model of the Peri- On the basis of the favorable comments, thepheral Vision Pisplay was installed in the package should be redesigned and univer-Universal Flight Trainer. The display op- salized so that it can be used on all simula-erates satisfactorily and the light line is tors, or manually operated for demonstra-clear and bright, moves as desired, and tions.

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AFFDL-TR-66-91

REFERENCES

I. W Grcnberg, Derodator. 400 Cyele - General Purpose. Dayton Labor ')ry Tech.Memo. #3, Link Group/Systems Division, General Precision, Inc.. 20 December, 1963.

2. E. D. Vinson, Transistorized Servo Amplifier. Dayton Laboratory Tech. Memo #2, LinkGroup/Systems Division, General Precision, Inc., 2 December, 1963.

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AFFDL-TR-66-91

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Figure 5. Pitch System Schematic

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Security Classification Ii, i oi DOCUMENT CONTROL DATA- R&D,ritv €1oai~licatin of title. b<oy e abstract anrtd indexing aatrnroiion .i of be entred w'.n de overall report Am claaltied)I ORIGINATING ACTIVITY (CoPor W. author)2 - RFPQRY SECUftITY C LASSIFICATION

Link Group, General Precision, Inc., UnclassifiedBinghamton, New York

3. REPORT TITLE

A PROTOTYPE PERIPHERAL VISION AIRCRAFT ATTITUDE DISPLAY

4. DESCRIPTIVE NOTES (Typ of report ad inchsive dates)

5. AUTHOR(S) (Last nmme, first nae, Initial)

Williams)fn, William R,

6. REPOT D*TE 70. TOTAL NO. OF PAG9S 7b. NO. OF PUPS

October 1966 197 2On CONTRACT OR GRANT NO. $a. OP. GINATOR*S REPORT NUMSER(S)

AF 33(615)2895. PRaojECT PO. 6190 AFFDL-TR-66-91

o. Task No. 619004 9b. ZTMEVPOR NO(S) (Any o .,.e,,,, imvybe...l .. A

d. 64-13210. AV AIL ABILITY/LIMITATION NOTICES

The distribution of this document is unlimited.

11. SUPPIL EIENTARY NOTES I1. SPONISOINO MILITARY ACTIVITYAir Force Flight Dynamics Laboratory (FDCR)Wright-Patterson Air Force Base, Ohio 45433

I3. ADSTRACT

An instrument is described for presenting attitude information to the pilot insuch a manner that he may maintain an awareness of his attitude through PeripheralVision without the necessity for looking directly at a specific instrument. The systemdoes this by projecting a line of light on the aircraft instrument panel and moving itin a manner similar to the motion of the real. horizon. A design criteria and adetailed engineering description of the working model are also presented.

DD I°JAN4 1473 UNCLASSIFIEDSecurity Classification

Im

UNCLASSIFIEDSecurity Classification

KEY WORDS ROL K . o-. ..... T ROLE

DisplayArtificial HorizonAttitude IndicatorLight LineProjection Systim

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