apollo experience report crew station integration volume iii spacecraft hand controller deveolopment

8/8/2019 Apollo Experience Report Crew Station Integration Volume III Spacecraft Hand Controller Deveolopment

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N A S A T E C H N I C A L N O T E NASA TN D-7884

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In

APOLLO EXPERIENCE REPORT -CREW STATION INTEGRATIONVolume I11 - Spacecraft Hand Controller DevelopmentFrank E . WittierLyndon B . Johnson Space CenterHonston, Texus 77058

N A T I O N A L A E R O N A U T I C S A N D S P AC E A D M I N I S T R A T I O N W A S H I N G T O N , D. C. M A R C H 1975


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1. Report No.NASA TN D-7884

4. T i t le and Subt i t l eAP OL L OE XP E R I E NC E R E P OR TCREW STATION INTEGRATION- OLUME IIISPACECRAFT HAND CONTROLLERDEVELOPMENT

7. A u tho r ($ )Frank E. Wit t ler

2. Government Accession No. 3. Recipient's Catalog No.

F n P e r f o r m l n g g k a t i o ; Name and Address

17 Key Words (Sugges ted by A uth or I s ))Hand Contro l ler * Crew StationThree-Axis Control l er 'Display SystemsVehicle Control'Att itude Control Control

Lyndon B. Johnson Space CenterHouston, Texas 77058

1 8 Dis t r ibut ion Sta tementSTAR Subject Category:1 2 (Astronautics, General)

5. Report DateMarch 1975

6. Performing Organization CodeJSC-07258

8. Performing Organization Report No.JS C S-41110. Work Unit No .956-23-00- 00- 7211. Contrac t or Grant No.

19 Securi ty Classi f (of this repo rt) 20 Securi ty Classi f (o f this page)Unclassified Unclassified

~-3. Type of Report and Period Covered12. Sponsoring Agency Name and Address Technical Note

21 NO o f Pages 22 Price22 $3.25

National Aerona utics and Space Administrat ionWashington, D. C . 20546 14. Sponsoring Agency CodeI

15. Supplementary Notes


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APOLLOEXPERIENCEREPORTEDITORIAL COMMITTEE

The material submitted for the Apollo Experience Repor ts(a se r i e s of NASA Technical Notes) w a s reviewed and ap-proved by a NASA Editorial Review Board at the Lyndon B.Johnson Space Cente r consis ting of the following mem be rs :Scott H . Simpkinson (Cha irman ), Richard R. Baldwin,James R . Bates, William M . Bland, J r . , Aleck C. Bond,Robert P. Burt, Chr is C. Critzos, John M. Eggleston,E. M . Fields, Donald T. Gregory, Edward B. Hamblett, J r . ,Kenneth F. Hecht, David N . Holman (Editor/Secretary),and Carl R. Huss. The prime reviewer for this reportw a s Kenneth F. Hecht.


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FOREWORD

This technical note documents experience gained in the area of spacecraft crewstation design and opera tions during the Apollo Prog ra m. Emphas is is given to thetime period ranging fro m ea rly 1964 up to, and including, the Apollo lunar landingmission of July 1969. This time period cover s th re e important phases of the ApolloPro gra m: the design phase, hardware construction, and mission operations.This technical note consis ts of five volumes. Volume I, "Crew Station Designand Development, '' gives a n overview of the total cre w station integration task. Vol-umes 11, III, IV, and V are spec ialized volumes, each of which is devoted to a basicfunctional area within the Apollo crew station. The subje ct of each volume is indicatedby i ts title, as follows.Volume 11, "Crew Station Displays and Controls"Volume 111, "Spacecraf t Hand Controller Development"Volume IV , "Stowage and the Suppor t Team Concept"Volume V , "Lighting Considerations"

Louis D. AllenLyndon B. Johnson Space Cente r

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CONTENTS

SectionSUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hand Contro ller Functional Specifications . . . . . . . . . . . . . . . . . . .Attitude Controll ers on the C M . . . . . . . . . . . . . . . . . . . . . . . . .The ACA on the LM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Translational Hand Controll ers on the CM . . . . . . . . . . . . . . . . . . . .The TTCA on the LM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CONCLUDING REMARKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .APPENDIX A.UNCTIONAL SPECIFICATIONS FOR APOLLOHAND CONTROLLERS . . . . . . . . . . . . . . . . . . . .APPENDIX B.PPROVED DEVIATIONS TO HAND CONTROLLER . . . . .

Page11333791011

121 5

V


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TABLES

Table Page. . . . . . . . . . . . . . . . . . . . . 4I BLOCK I RHC SPECIFICATIONSI1 6BLOCK I1 RHC SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . .

8I1 LUNAR MODULE ACA SPECIFICATIONS. . . . . . . . . . . . . . . . .911

IV BLOCK I THC SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . .BLOCK I1 THC SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . .

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FIGURES

Figure Page. . . . . . . . . . . . .Mercury spacecraft three-axis hand controller 2. . . . . . . . . . . . . . . . . .Gemini spacecraft attitude controller 2. . . . . . .Gemini spac ecra ft translational-maneuver hand cont roll er 2. . . . . . . . .Functions of th e Block I CM rotational hand controller 4. . . . . . . .Functions of the Block 11CM rotational hand controller 66 Block I1 rotational control. Pitch torque plotted as a functionof deflection with incre asin g torque . . . . . . . . . . . . . . . . . . 7

. . . . . . . . . . . .Functions of the LM attitude controller assembly 78 Lunar module ACA roll- axi s torque, voltage, and switchrequirements plotted as a function of displacement . . . . . . . . . . 89 Functions of the Block I CM THC . . . . . . . . . . . . . . . . . . . . 9. . . . . . . . . . . . . . . . . . . .0 Functions of the Block I1 CM THC 1011 Functions of the LM TTCA . . . . . . . . . . . . . . . . . . . . . . . 1012 Handgrip force and output voltage plotted as a function of

displacement on the LM TTCA in the throttle-controlmode. When the handgrip is moved through the 51 to5 6" position in either direction, the minimum jump infriction is 3 3 . 9 cm-N ( 3 in-lb) . . . . . . . . . . . . . . . . . . . . . 11. . . . . . . . . . . . .- 1 Pitc h torque plotted as a function of deflection 1 3A - 2 Roll torque plotted as a function of deflection and measuredat 1 0 . 4 7 8 centimeters (4.125 nches) above roll pivot

(i.e., at pitch pivot) 1 4A-3 Yaw torque plotted as a function of deflection 1 4

. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .A - 4 Deflections fo r roll, pitch, and yaw . . . . . . . . . . . . . . . . . . . 14A-5 Controll er axes with respect to crewman. The angle e shouldbe established such that the controller input axe s a r e obvious

to the pilot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 4

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APOLLO EXPER IENCE REPORTCREW STAT1 ON I NTEGRATI O N

VOLUME I I - PACEC RAFT HAN D CONTROLLER DEVELOPMENTB y F r a n k E. W i t t le rL y n d o n B . J o h n s o n S pa ce C e n t e r

S U M M A R Y

During the development of con trol techniques for Proje ct M ercury, rudder pedalswere determined to be unsuitable for control in the yaw axis because of crew stationand environmental inter face problems. The se conditions led to the development of thethre e-ax is fly-by-wire hand cont roll er used for the Apollo manned spacecraft .To establish a guideline for the complex par am et er s of a three-axis controller,a functional specification was developed that established the mechanical forces andelect ri cal functions of the Apollo spacecra ft hand cont roll ers. This specification al soestablished a commonality requirement between the command module and the lunarmodule hand controllers and identified human engineering requirements.

INTRODUCTIONThe Apollo spacecraft attitude (rotational) and translational hand controllers pro-vided a linkage fr om the crewman to the stabilization and control syst em (SCS) thatenabled the crewman to override the automatic control mode and manually insert pulse,direct, or proportional commands i n the pitch, roll , and yaw axes or any combinationof thes e axes. The six hand cont rol lers that existed during the Apollo Pr og ra m includedthe command module (CM) Block I rotational hand controller (RHC), the CM Block 11RHC, the CM Block I translational hand controller (THC), the C M Block JI THC, thelunar module (LM) attitude controller assembly (ACA), and the LM thrust and trans-lation control assembly (TTCA).The Apollo spacecraf t hand cont roll ers repre sen t the state of the art in hand con-troller design as i t has evolved through the manned space-flight programs. Initially,rudder pedals we re envisioned for the Mercury s pacecraft yaw axis, with a two-axishand cont roll er for the pitch and ro ll axes . However, high g-loads, res tri cted legmovement within the spa ce su it, and weight and spa ce limitations forced the design ofa three-axis attitude controller (fig. 1). For the Mercury spacecraft, the controllerbasically consisted of a se t of linkages controlling var iab le valves on one se t of th rus t-e r s with limi t switches on the linkages for the fly-by-wire mode driving a second set of


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Safetyin%-Ya w

Figure 1. - Mercury spacecraftthree-axis hand controller.

Figure 2. - Gemini spacecra ftattitude controlle r.

thr ust ers . The Gemini spacecra ft attitudeand translationa l controller design (figs. 2and 3) eliminated many of the mechanicallinkages present in the Mercury design andprovided a complete and improved fly-by-wir e syst em. The Apollo spac ecra ft con-tro l ler s represent an even more significantrefinement.During th e development of the Apollocontrols, a functional specification for atti-tude controllers was established to main-tain the requirement f o r commonalitybetween the CM rotational controller andthe lunar module (LM) attitude controllerand to provide a baseline for controller feeland function.applied to the Apollo Block 11 CM RHCThis specification was fi rs t

C o m m a n d p i l o t ' s p a n e l,~

Stowed posi t ionI - .\ I '.

h a n d c o n t r o l le r

~

R i g h t - h a n d s w i t c h a n dc i r c u i t b r e a k e r p a n e l

Figure 3 . - Gemini spacecraft translational-maneuver hand controller,

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during the early developmental phases and to the LM attitude controller assembly(ACA) during the design phase. Two attitude cont rol ler s were instal led in both the CMand LM to provide redundant c ont ro llers and additional control inputs during peak work-load periods.The CM translational controller assembly provided the crewmen with the capa-

bility to is su e disc ret e manual commands in each axis (X, Y, nd Z). It al so providedabort-enable and autopilot-disable capability. The L M TTCA provided the crewmenwith the capability to i ss ue di scr ete manual commands in each axis (X , Y , and Z ) . Italso provided a thro ttl e mode fo r varying the thrust of the descent engine.A s an aid to the rea de r, where necessary the original units of meas ure have beenconverted to the equivalent value in the Systkme International d'Unit6s (SI). TheSI units are written first, and the original units are written parenthetically thereafter.

D I S C U S S I O NH a n d C o n t r o l l e r F u n c t i o n a l S p e c i f i c a t io n s

During the development of the Apollo Block I hand controllers, the need for afunctional specif ication to define and maintain the requi rement for commonality betweenthe CM and LM cont ro lle rs became evident. Although this specification (appendix A)established the feel (i.e. , fo rce and deflection), con trol functions, soft stop requ ire -ments, and handle design, it w a s flexible enough t a accommodate mechanization of eachcontroller to its assigned task. The vendor requested and was granted three deviationsto the specification (appendix B).Much of the specif ica tion data w a s obtained by conducting laboratory simulations

that evaluated different combinations of force and deflection characteristics. A single-ax is te s te r , which consisted of a handgrip mounted on a variable-control device, wasused as a measurement device for the simulation during which simple tracking taskswe re perf orm ed by the crewmen. By changing the position of the tes te r handgrip,torque and displacement va riations (including soft st ops ) could be made in any oneaxis . The mechanical setup of the te st er could be converted to measure the torque atbreakout, ra te o r torque incr eas es fro m breakout to soft stop, the torque step at aconstant deflection at the soft stop, the rate of torque incre ase f ro m soft to hard stop,and the hysteresis .

A t t i t u de C o n t r o l le r s o n t h e CMWhen the functional requirements specification w a s approved, a design fr ee ze w a simposed on the Block I attitude controller. This controlle r was redesigned to the spec-ified req uiremen ts , and the new configuration became known as the Block 11 controller.Block I RHC. - The Block I RHC was a smal l, simple, compact, three-a xis con-trol ler with three switches and a linear tr ansform er output (rot ary variable-differentialtra nsf orm er (RVDT)) in each axis. A quick-disconnect dovetail mounting bracket and

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a long cable permitted relocation of thecontroller within the spacecraft. TheRHC, although designed for right-handuseonly, could be trans ferr ed to the navigationstation or to another crewman's couch.Thi s handle was designed without space-cr af t communications push- to- talk switches(fig. 4 and table I). A mechanical lockingpin extended through the handle of theBlock I RHC into the RHC base; this pinprevented inadvertent RHC activationduring nonoperating periods. Late in thedesign phase of the Block I RHC, soft stopswere added to the roll axis only to providethe crewmen with a manual-override outputin roll f or lift-vector control during entry.

0 Pivot point1+1xtreme position_ _ _

Neutral Neutralposition position

l e f tRear Neutralposition

f i lch motions Ym motions Roll motionsFigure 4. Functions of the Block I CMrotational hand contro ller.

TABLE I. - BLOCK I RHC SPECIFICATIONS

ParameterRVDT input voltage, V ac, at 400 Hz, 1 W . . . . . . .RVDT output voltage, V ac, a t 400 Hz, 1 W . . . . . . .Switch voltage, V dc . . . . . . . . . . . . . . . . . . .Switch inductive load, A . . . . . . . . . . . . . . . . .Switch res ist ive load, A . . . . . . . . . . . . . . . . .Maximum dimensions, cm (in. )

Height . . . . . . . . . . . . . . . . . . . . . . . . .Length . . . . . . . . . . . . . . . . . . . . . . . . .Width . . . . . . . . . . . . . . . . . . . . . . . . . .Cable length . . . . . . . . . . . . . . . . . . . . . .

Weight (including external cable andconnector), kg (lb) . . . . . . . . . . . . . . . . . . .

Value-60 o 4.2

28 (+2, -3) 147

23.50 (9.25)14.63 (5.76)7.11 (2.80)

467.4 (184.0)

2.22 (4.9)

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Block II RHC. - The force and displacement cha rac ter ist ics of the Block 11 RHCwere an improvement over those of previous models. Although many operational prob-le ms occu rred with the RHC, most were discovered and correcte d by the vendor.Because of training req uirem ents, seven early model rotational hand controll ers weredelivered. Several problems were experienced with these units during the trainingsess ions. The most significant problem was multiaxis interference; that is , a maxi-mum deflection in plus roll and minus pitch caused the pitch-sector ge ar to hit thefr ame and for ce the switch package and the RVDT out of calibration. An offset nullresulted, and the pitch breakout switch remained closed. This problem was resolvedby machining the fr am e for adequate clearance .

During preliminary training sessions with the Block 11 rotational hand controllers,the c rewmen noted that the fuel-budgeting technique developed fo r the Gemini controlle rwas not possible fo r the Apollo RHC. On the Gemini spacecra ft, a minimum jetimpul se could be obtained'by quickly tapping the contro ller handle in the de sir ed direc-tion. A sho rt engine pulse' would res ult , and the co ntro ller handle would be returnedby sp rin gs to the neutral position without further jet fir ings . When this technique w a str ied with the Apollo RHC, the handgrip overshot i t s neutr al position in the oppositedirection because it was underdamped, thus causing undesired jet firings. A l l handcon tro lle rs we re test ed by tapping the handle sufficiently fo r a right-roll impulse andmonitoring the handle overshoot fo r a left-roll impulse. N o overshoot impulse existedon the Gemini and Block I CM attitude cont roll ers; however, i n the Block II CM andLM attitude controllers, a negative-roll impulse was observed. Another te st consistedof commanding a full-right- roll deflection to the soft stops, rel eas ing the handle, andmeasuring the time required f or the controller t o reac h and stay within the detentswitches. The following tes t resu lt s were obtained.

Attitude controller teste d Response time, secGemini 0.120Apollo :

Block I CM ,020Block 11 CM ,200LM .400

The vendor engineering specification for the LM ACA required that the overshoot notexceed 1.0 second in roll and 0.5 second in pitch and yaw. The Apollo spacecra ftcomputer compensated fo r the overshoot obtained by tapping the handle; therefore, theBlock II hand contro ller did not r equ ire modification.

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The final design fo r the CM RHC Maximumdeflection,all axes,(fig. 5 and table 11) cons isted of 3 rotary Push-to-talk switchPitchvariable-diff erential tra nsf orm ers and18 microswitches; that is, one breakoutswitch and two direct switches beyond eachsoft stop (fig. 6). One of the two directswitches was redundant. The mechanicallocking pins were redesigned within thefor electrical disablement. Scissor-typeaxis to eliminate hys ter esi s and provide areliable mechanical zero. A symmetricalhandle, equipped with a push-to-talkswitch, was designed fo r left- o r right-hand operation.

RHC; two interlock swit ches wer e providednull-positioning spri ngs we re used i n each lo p view Side view End view

device

Figure 5.- Functions of th e Block II CMrotational hand contr oller.

Maximum dimensions , cm (in. ):Height . . . . . . . . . . . . . . . . . . . . . . . .Length . . . . . . . . . . . . . . . . . . . . . . . .Width . . . . . . . . . . . . . . . . . . . . . . . .Cable length . . . . . . . . . . . . . . . . . . . . .I

TABLE II. - BLOCK 11 RHC SPECIFICATIONS

RVDT input vol tage , V ac , at 400 Hz . . . . . . . . .RVDT output voltage, V ac, at 400 Hz . . . . . . . .Switch voltage, V dc . . . . . . . . . . . . . . . . . .Switch inductive load (direct), A . . . . . . . . . . .

ValueParameter I26 + 0.32

0 o 4. 58 ? 0.32285

27.28 (10.74)18.52 (7.29)I

Switch res ist ive load (breakout andpush to test) , A . . . . . . . . . . . . . . . . . . . 3

7.70 (3.03)274.3 (108.0)

. . . . . . . . . . . . . . . . . 3.6 (8)Ieight (including external cable andconnector), kg (lb)6


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45265[ 11339 - 30226 - 20113- o 0

g 113 - 10226 - 20CT

Nominal hard stopINominaIwitch actuationirect-jj

Nominal soft stop

I switch actuationc/i4521 . . i f l a ,

8 4 0 4 8 1265 5012Displacement, deg

Figure 6. - Block II rotational control.Pitch torque plotted as a functionof deflection with increasing torque.The A C A on the LM

NeutralpositionDitch rnntinnr Len

Neutralposit onYa w motions

The basi c design configuration of theLM ACA (fig. 7 and table 111) passed alldesign verification and quality testing. A sproblems occurred, they were correctedwithin specification requi rement s. Costlylast-minute design changes we re minimized,

Roll motions Neutralposition

Figure 7. - Functions of the LM attitudecontroller assembly.

and a high-qfiality hand controller package resulted . A rigid swi tch package w a s used foreach axis to avoid wire-bundle flexing. Each package contained 14 witches and a trans-ducer, which was actuated through gear and linkage ass emb lie s to the handle. To avoidthe torque buildup to switch actuation (as was experienced with the Gemini controll er),a force-feedback technique wa s developed fo r switch pa ir s so that, as one switch opened,another closed, thus canceling any force buildup and undesirable f eel at the handle.The req uir eme nts fo r interna l logic functions f o r the pitch and rol l axes anddi rec t thr us te r c ontrol incre ased the number of switches to 14 per axis. The internal

switch logic, coupled with the multiple power paths to the controller, complicatedfailure-isolation procedures; therefore, special external isolation switches were addedf o r rapid contro ller disablement. The increased number of switches did, however,offer m or e capability fo r isolating a failed switch. Because of the requirement to stowthe con tro lle rs during certai n intravehicular activities and during ingre ss and egre ss,the controll ers were mounted to foldable armr est s. This design feature required anumber of refinements since it introduced problems including interference, wire-bundleflexing, and inadvertent switch clos ur es during stowage. Additional probl ems

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concerning excessive cable length, cable routing, stowage mechanization, andcontroller-vehicle inte rface we re alleviated before the first manned mission.TABLE III. - LUNAR MODULE ACA SPECIFICATIONS

Linea r-tr ansfo rmer output voltage to softstop, V ac, at 800 Hz, 1 . 5 W . . . . . . . . . . .Switchvoltage, V dc . . . . . . . . . . . . . . . . .Switch inductive load, A . . . . . . . . . . . . . .Switch res ist ive load, mA . . . . . . . . . . . . .Maximum dimensions, cm (in.):

H e i g h t . , . . . . . . . . . . . . . . . . . . . . .L e n g t h . . . . . . . . . . . . . . . . . . . . . . .Width . . . . . . . . . . . . . . . . . . . . . . .Cable length . . . . . . . . . . . . . . . . . . . .

Weight (including external cables andconnectors), kg (lb) . . . . . . . . . . . . . . . .

O t o 2 . 8 7 + 0 . 0 728 (+2, -3 )

1500

2 5 . 5 5 ( 1 0 . 0 6 )1 6 .9 9 ( 6 . 6 9 )1 0 . 1 6 ( 4 . 0 0 )

9 1 . 4 4 ( 3 6 . 0 0)

2 . 0 4 ( 4 . 5 0 )

The 14 switches and the RVDT withinthe LM ACA performed the following func-tions. A s the control handle w as moved 2 94 V acfr om neutral (fig. 8) , the detent switchesclosed, preparing the syste m for a pulse-dir ect fir ing of the jets. A t 2" to 3 deflec-tion, the pulse-direct switches closed, andthe appropriate reaction control syste m299 5cm-N(2 6 5in-lhl

175 2 cm N141 3 cm-N(15.5 in-lblRCS) je ts fired. At a displacement of /approximately lo", the soft stops separated D e t e n tthe pulse-direct mode from the manual-

override mode. Movement of the handlebeyond the soft-stop position closed thefour manual-override switches, whichcaused dir ect firing of all four jets. TheRVDT output was variable (0 to 3 volts,800 hertz ), either in or out of phase withrespe ct to direction, fro m null to the softstops. displacement.

switch

Displacement. de gFigure 8. - Lunar module ACA roll-axistorque, voltage, and switch require-ments plotted as a function of

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Translational Hand Controllers on the CMTwo translational hand controllers were insta lled i n the Apollo Block I spacecraftfo r redundancy. During the Block I1 redes ign, redundant switching was incorporated inthe controller s o that the sep ara te backup controller was eliminated.Block I THC. - The Block I THC was a simple T-handle displacement-type controlwith two microswitches each in the X - , Y - , and Z-axes. The autopilot-disable andlaunch-abort modes we re initiated, respectively, by clockwise or counterclockwiserotation of the T-handle grip from 12" to 17". A problem existed in these modes in theCM THC because a gr eat er for ce was required to ro tate the handle out of the disable orabort mode than out of detent. Th is situation, which caused the handle to go beyonddetent into the opposite mode, w a s annoying but was not a n operational problem.The translational modes were actuated by a 0.89-centimeter (0.35 inch) dis-placement i n or out for the X-axis and a 6" deflection of the handle fo r Y- or Z-axis.The crewman's push-to-talk inter com switch was insta lled i n the top of the T-handle,and a mechanical sliding lock to a r m the THC was located on the top cover of the handle

(fig. 9 and table IV).Block I1 THC.- The Block I1 THC w a s mounted on the left ar mr es t of thecommander's (CDR's) cocch on a dovetail mounting bracket . A s in the Block Idesign, the T-handle rotation provided the CDR with the capability to initiate an abort

Control-shaft lock \wchn?

MTop view

X-axis control

No t e Dashed lines ind ica temovement b o u n d a r i e sSide view

TABLE 1V.- BLOCK I THC SPECIFICATIONS

ParameterInput voltage to switches, V dc . . . .Switch ratings:

Sensitive swit chesMaximum re sis tiv e load, A . . .Maximum inductive load, A . . .Nominal operat ing load, mA . . .

Push-to-talk switchMaximum resistive load, A . . .Maximum inductive load, A . . .Nominal opera ting load, mA . . .

Maximum dimensions, cm (in. ) :Height . . . . . . . . . . . . . . . .Length (grip extended) . . . . . . .Width . . . . . . . . . . . . . . . .Cable length . . . . . . . . . . . .

Weight (including cable), kg (lb) . . .

Value28 c 3

53

100 to 5 0 0

31

2 5 0

1 4 . 8 3 ( 5 . 8 4 )17.78 (7.00)7 . 7 0 ( 3 . 0 3 )

46 7 + 5 (184 f 2)2 . 3 8 ( 5 . 2 5 )

Figure 9. - Functions of theBlock I CM THC.

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or to override the autopilot mode. Rotating the T-handle counterclockwise initiated anabort during the launch sequence. Rotating the handle clockwise disabled the CM com-puter and engaged the SCS backup configuration selected or switched f ro m SCS auto-matic thrust vector cont rol (TVC) to manual TVC, depending on the position of panelswitches. The overshoot problem of the Block I THC was c orre cted in the Block IIdesign. A vertical or horizontal deflection of the T-handle i n o r out by 1 . 2 7 centime-t e r s ( 0.5 inch) provided the CMP with manual control i n translation of the Z - , Y - , o rX-axis or any combination of those ax es (fig. 10 and table V ).

X-axis control

Side view

Control-shaft lock7 witching\Y 'I

Top view

- L t Y-axis control

Figure 1 0 . - Functions of theBlock I1 CM THC.

Thrusti translat ionT-handle control--\

.X-axis++X-axis translat ion(descent-engine control)

translation jets+Z-axis translat ionl R C S control )

-X-axis trans a io n(descent-engine control) control

Figure 11. - Functions of theLM TTCA.The TTCA on the LM

The two LM thrust and translation c ontroll er ass emb li es provided the LM crew-men with manual translational control of all three axes, with deflection of the T-handleby actuation of detent switches . The feeling of st if fn es s with deflection of the con-troll er handle was due to the use of moving switch packages and graphite -type lubr i-cants. By sliding a lev er on the side,of the cont rol ler, control in the X-axis (fig. 1 1)became a manual-throttle mode fo r the descent engine. A soft stop was designedat 53" deflection of the throt tle handle, which re pr es en te d a 0- to 53-percent thrust ofthe descent engine for fine control during landing maneuvers.were 10" of handle deflection for controll ing 53 to 100 percent of the descent-engineBeyond the Soft Stop

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thrust . The amount of frict ional dra g onthe handle in the thro ttle mode (fig. 12)could be varied by an external knob on thelower left side of the cont rol ler .

158.2 r 14r Handle center wsition. +33O3 135.6

> 113.0'2I 90.47 . j2 1 g 45.23 p 22.60 0Displacement, deg

Figure 12. - Handgrip forc e and outputvoltage plotted as a function ofdisplacement on the L M TTCA inthe throt tle-contro l mode. Whenthe handgrip is moved through the51" to 56" position in either direc-tion, the minimum jump in frictionis 33.9 cm-N (3 in-lb).

TABLE V. - BLOCK II THC SPECIFICATIONS

ParameterInput voltage to switches, V dc . . .Switch ratings:Z - , Y -, and X-axis switch

Clockwise rotary switchCounterclockwise rotary

resistive loads, A . . . . . . .resis tive loads, A . . . . . . .switch resistive loads, A . . .

Maximum dimensions, cm (in. ):Height . . . . . . . . . . . . . . .Length (grip extended) . . . . . .Width . . . . . . . . . . . . . . .Cable length (including

connectors) . . . . . . . . . . .Weight (including cable) ,kg (lb) . . . . . . . . . . . . . . .

Value28 (+2, -3)

222

16.03 (6.31)18.69 (7.36)9.73 (3.83)

229 (90)2.7 (6)

CONCLUD I NG REMARKSIt was demonstrated i n the Apollo Pr ogr am , as in Project Mercury and theGemini Program, that the three-axis hand controller is very adaptable to the space-craft environment. However, it w a s not conclusively established that a three-axiscon tro lle r would be acceptable in a shuttle-type vehicle when used in a dual mode asboth an atmospheric and nonatmospheric control device. The functional specificationf o r attitude control lers developed during the Apollo Pr og ra m provides flightcrewoperational design requirements for u se in spacecraft applications.For futur e pr og ram s, the amount of int ernal el ect ric al components and logicshould be minimized as w a s done in the design of the command module rotational handcontrollers (as opposed to the design used in the lunar module attitude controllerassembly) . Internal components should be minimized or tran sfe rred to external blackboxes to reduce the possibility of massive internal failu res and to permi t a straight-

for ward approach for normal or emergency powerdown of cont ro llers; that is, byreducing the power-signal paths at the controller interf ace.

Lyndon B. Johnson Space CenterNational Aeronautics and Space AdministrationHouston, Texas, September 13, 1974956-23-00-00-72

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A P P E N D I X AFUNCTIONAL SP EC IF IC AT ION S FOR APOLLO HAND CONTROLLERS

S CO PE A N D C L A S S I F I C A T I O NThis specification establishes the basic functional characteristics required forthe hand controllers to be used in the Apollo command module and lunar module andis applicable to any three-axis attitude side-arm controller used for manual controlof space vehicle attitudes (pitch, rol l, and yaw).

REQUl REMENTSC o n t r o l l e r F o r c es

The data showing torque plotted as a function of deflection in figures A -1 to A - 3represe nt the required force charact eristi cs in the pitch, roll, and yaw axes, resp ec-tively. These cha ract eris tic s include breakout, g radien t, soft stops, and maximumforces.of the breakout spring fo rce so that the actual measured f orces fall within the bandsshown in figures A - 1 to A-3.

The hysteresis inherent in each controller shall be held to within *lopercent

C o n t r o l l e r D e f l e c t i o n sThe deflections for rol l, pitch, and yaw shal l be as shown in figure A - 4 .Nominally, the soft stops sha ll be encountered at k10" and the hard stops a t A 1 . 5in all axes.

C o n t r o l l e r A x esThe axes shall be as shown in figure A - 5 . The pitch axis shall be at the palmof the hand; the yaw axis, through the hand perpendicular to the pitch pivot; and theroll-axis pivot, 1 0 . 1 6 (-0.0, + 2 . 5 4 ) centimeters (4 .00 ( -0 .0 , + l . ) inches) below andperpendicular to the normal pitch axis.

R e l a t i v e L o c a t i o n of C o n t r o l l e r A x esController axes relative to the pilot axes. - A s shown in figu re A - 5 , the control-ler axes in the installed position shall be alined relative to the corresponding pilot-labeled vehicle axes so that the controller input axes are obvious to the pilot.

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Controller ax es relative to the centerline of the fo re ar m. The normal positionof the controller yaw axis shall be such that the vert ica l angle between this axis andthe centerline of the fo re ar m is 110" 2 5" to allow fo r nor mal positioning of the hand(fig. A - 5 ) .

509- 45-452 - 403 % - 3 5 -339 - 3 0 -283 - 25226 - 20170 - 15113 - 1 0 -

5 7 - ?'

C o n t r o l- S y s te m s M o d e - A c t ua t io n P o i n t s W i t h i n C o n t r o l l e r D e f le c t io n s

-

Frictional---

Direct- and pulse-mode5 -

Proportional output. - The proportional output shall be active through the entirecontroller deflections ( + l o " ) except for the dead band a t neut ral. This dead bandshall not exceed +1 handle deflection (mechanical dead'band). The proportionaloutput shall always fall outside the mechanical dead band of the controller to preventinadvertent inputs.

339

39652

Direct-mode actuation. - The direct mode shall be actuated at 25 percent(2 . 5 " + 1 ) of total normal deflection in al l axes.

- 30-- 4035-98

Emergency direct-mode actuation. - The emergency direct mode shall be actu-ated at a point beyond the soft stops and before contacting the hard stops.

Pulse-mode actuation. - The pulse mode shall be actuated at the sa me pointa s the direct mode.Handgrip

The desired handgrip shape shall beas shown in figure A - 5 . Deviations to thi sshape (to accommodate switching, etc . )shall be submitted to the NASA Lyndon B.Johnson Space Center (formerly theManned Spacecraft Center) for writtenapproval or disapproval.

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Emergencydirect-modeactuation point

+Direct- and Dulse-modeI actuation p i n t

inches) above roll pivot ( i .e . , atpitch pivot). 12 10 8 b 4 2 0 2 4 6 8 10 12Dellection. deqFigure A - 3 . - Y aw torque plotted as afunction of deflection.

Neutral

Figure A - 4 . - Deflections for roll, pitch,and yaw.

Control lerya w axis

I_ ControllerControl lerrol l axis

rol l axis

Figure A - 5 . - Controller a xes with resp ectto crewman. The angle e should beestablishedssuch that the controllerinput axe s a r e obvious to the pilot.

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A P P E N D I X BAPPROVE D DE VIA TIO NS TO HAND CONTROLLER

FUNCTIONAL SPEC1F I C A T I O N SD e v i a t i o n 1

The force tolerance shal l be such that, when measur ed in an increasing forcedirection, the maximum deviation fro m the nominal for ce value at any given pointalong the force-and-deflection curve (figs. A-1 to A-3) shall not exceed lt20 percentof the nominal fo rce values. When mea sured in a decreasing force direction, theforce shall not be less than 60 percen t of the force value. The ratio nale for thisrequest is explained in the following discussion.Th e tolerance curve defined in the specification does not appea r to be nece ssaryto give the handle the prop er feel and may indeed be undesira ble because of the follow-ing penalties that are inherent in the mechanization. By holding the up and downforces to a tight tolerance, the breakout force is held to an even tighter toleran ce s othat the nonlinearities of the up- and down-force gradients should not cause the meas-ured forces to fall outside the toleranc e band. This toler ance and the high load limit(136 kilog rams (300 pounds)) requi re the manufacturer t o use speci al precision com-ponents, which raise the per-unit cost.

D e v i a t i o n 2The proportional output shall be active through the ent ire controller deflection(* lo " ) except for the dead band a t neutral. This dead band (mechanical and elect rical )sha ll not exceed a controller deflection of 1. 75" lt 0.25 (when measur ed in an inc rea s-ing fo rce direction).of the cont rol ler to prevent inadver tent inputs. The following discu ssion explains therationale for this request.

The proportional output shall always fall outside the dead band

The intent of the specification is to cause the vehicle to st ar t to rotate at 1" ofincre asing handle deflection and to slow, as close as possible, to a dead stop as thehandle passes through 1 f de creasing handle deflection.Although moving the electrical breakout point in toward the neutral point will

dec rea se the handle deflection neces sary to s ta rt the vehicle rotating, it will notreduce the vehicle rates below the dead band ra te s (without having to command anopposite rate). Extensive modifications to either the system o r the controller orboth mus t be made with resultan t undesirable side effects (weight increa se, volumeinc rea se, reliability decrease, cost increase, and peculiar operating characteristics).The requested 1. 75" allowable deflection repre sen ts a compr omise between theBlock I value of 2 .5" and the Block I1 specification of 1 .0 ".

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Deviation 3The direct mode shall be actuated at 17.5 percent (1.75' ~t .25" as measuredin an increasing f orc e direction) of t otal nor mal deflection in all axes.for this request is discussed in the following paragraph. The rationale

Changing the location of the di rect - and pulse -mode actuation point to1. 7 5 " + 0.25' al so allows the breakout switches to per fo rm these switching functions.The change red uces the total count of intern al co ntrol switches fr om the 16 switchesrequir ed by the specification to 12 switches. Reducing the total switch count allowsthe rotational-control volume to be reduced by approximately 120 X 10(73 cubic inches) and the box weight to be reduced by approximately 0.45 kilogram(1 pound).

-5 cubic meters

16 NASA-Langley , 1975 S-411


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apollo experience report crew station integration volume iii spacecraft hand controller deveolopment

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