Revision feabfcc6514f3fb411605a6982bc539a220b8fe6 authored by Mike Stewart on 07 August 2021, 22:38:19 UTC, committed by Mike Stewart on 07 August 2021, 22:38:19 UTC
1 parent 9587743
GIMBAL_LOCK_AVOIDANCE.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: GIMBAL_LOCK_AVOIDANCE.agc
## Purpose: A section of Luminary revision 178.
## It is part of the reconstructed source code for the final
## release of the flight software for the Lunar Module's
## (LM) Apollo Guidance Computer (AGC) for Apollo 14. The
## code has been recreated from copies of Zerlina 56, Luminary
## 210, and Luminary 131, as well as many Luminary memos.
## It has been adapted such that the resulting bugger words
## exactly match those specified for Luminary 178 in NASA
## drawing 2021152N, which gives relatively high confidence
## that the reconstruction is correct.
## Reference: p. 369
## Assembler: yaYUL
## Contact: Ron Burkey <info@sandroid.org>.
## Website: www.ibiblio.org/apollo/index.html
## Mod history: 2019-08-14 MAS Created from Zerlina 56.
## Page 369
BANK 15
SETLOC KALCMON1
BANK
# DETECTING GIMBAL LOCK
LOCSKIRT EQUALS NOGIMLOC
NOGIMLOC SET
CALCMAN3
WCALC LXC,1 DLOAD*
RATEINDX # CHOOSE THE DESIRED MANEUVER RATE
ARATE,1 # FROM A LIST OF FOUR
SR4 CALL # COMPUTE THE INCREMENTAL ROTATION MATRIX
DELCOMP # DEL CORRESPONDING TO A 1 SEC ROTATION
# ABOUT COF
DLOAD* VXSC
ARATE,1
COF
STODL BRATE # COMPONENT MANEUVER RATES 45 DEG/SEC
AM
DMP DDV*
ANGLTIME
ARATE,1
SR
5
STORE TM # MANEUVER EXECUTION TIME SCALED AS T2
SETGO
CALCMAN2 # 0(OFF) = CONTINUE MANEUVER
NEWANGL +1 # 1(ON) = START MANEUVER
# THE FOUR SELECTABLE FREE FALL MANEUVER RATES SELECTED BY
# LOADING RATEINDX WITH 0,2,4,6, RESPECTIVELY
ARATE 2DEC .0088888888 # = 0.2 DEG/SEC $ 22.5 DEG/SEC
2DEC .0222222222 # = 0.5 DEG/SEC $ 22.5 DEG/SEC
2DEC .0888888888 # = 2.0 DEG/SEC $ 22.5 DEG/SEC
2DEC .4444444444 # = 10.0 DEG/SEC $ 22.5 DEG/SEC
ANGLTIME 2DEC .0001907349 # = 100B-19 FUDGE FACTOR TO CONVERT
# MANEUVER ANGLE TO MANEUVER TIME
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