Source Code

017955,000001: # Copyright: Public domain. 017956,000002: # Filename: GIMBAL_LOCK_AVOIDANCE.agc 017957,000003: # Purpose: Part of the source code for Comanche, build 055. 017958,000004: # It is part of the source code for the Command Module's (CM) 017959,000005: # Apollo Guidance Computer (AGC), Apollo 11. 017960,000006: # Assembler: yaYUL 017961,000007: # Reference: pp. 412-413 017962,000008: # Contact: Onno Hommes <ohommes@cmu.edu>. 017963,000009: # Website: www.ibiblio.org/apollo. 017964,000010: # Mod history: 05/07/09 OH Transcription Batch 1 Assignment 017965,000011: 017966,000012: # The contents of the "Comanche055" files, in general, are transcribed 017967,000013: # from scanned documents. 017968,000014: 017969,000015: # Assemble revision 055 of AGC program Comanche by NASA 017970,000016: # 2021113-051. April 1, 1969. 017971,000017: 017972,000018: # This AGC program shall also be referred to as Colossus 2A 017973,000019: 017974,000020: # Prepared by 017975,000021: # Massachussets Institute of Technology 017976,000022: # 75 Cambridge Parkway 017977,000023: # Cambridge, Massachusetts 017978,000024: 017979,000025: # under NASA contract NAS 9-4065. 017980,000026: 017981,000027: # Refer directly to the online document mentioned above for further information. 017982,000028: # Please report any errors to info@sandroid.org. 017983,000029: 017984,000030: 017985,000031: # Page 412 017986,000032: 15,2000 BANK 15 017987,000033: 22,2000 SETLOC KALCMON1 017988,000034: 22,2000 BANK 017989,000035: 017990,000036: 22,2737 E6,1661 EBANK= BCDU 017991,000037: 017992,000038: # DETECTING GIMBAL LOCK 017993,000039: 22,2737 22,2737 LOCSKIRT EQUALS WCALC 017994,000040: 22,2737 70740 WCALC LXC,1 DLOAD* 017995,000041: 22,2740 01130 RATEINDX 017996,000042: 22,2741 04771 ARATE,1 017997,000043: 22,2742 45002 SR4 CALL # COMPUTE THE INCREMENTAL ROTATION MATRIX 017998,000044: 22,2743 44530 DELCOMP # DEL CORRESPONDING TO A 1 SEC ROTATION 017999,000045: # ABOUT COF 018000,000046: 22,2744 74343 DLOAD* VXSC 018001,000047: 22,2745 04771 ARATE,1 018002,000048: 22,2746 03343 COF 018003,000049: 22,2747 77721 MXV 018004,000050: 22,2750 05003 QUADROT 018005,000051: 22,2751 17311 STODL BRATE 018006,000052: 22,2752 03365 AM 018007,000053: 22,2753 55605 DMP DDV* 018008,000054: 22,2754 05001 ANGLTIME 018009,000055: 22,2755 04771 ARATE,1 018010,000056: 22,2756 77661 SR 018011,000057: 22,2757 20606 5 018012,000058: 22,2760 27317 STOVL TM 018013,000059: 22,2761 03311 BRATE 018014,000060: 22,2762 77761 VXSC 018015,000061: 22,2763 05025 BIASCALE 018016,000062: 22,2764 03275 STORE BIASTEMP # ATTITUDE ERROR BIAS TO PREVENT OVERSHOOT 018017,000063: # IN SYSTEM 018018,000064: 22,2765 77614 SETGO # STATE SWITCH CALCMAN2 (43D) 018019,000065: 22,2766 01035 CALCMAN2 # 0(OFF) = BYPASS STARTING PROCEDURE 018020,000066: 22,2767 45032 NEWANGL +1 # 1(ON) = START MANEUVER 018021,000067: 018022,000068: 018023,000069: 22,2770 00044 15053 ARATE 2DEC .0022222222 # = .05 DEG/SEC 018024,000070: 018025,000071: 22,2772 00221 24255 2DEC .0088888889 # = .2 DEG/SEC 018026,000072: 018027,000073: 22,2774 00554 02660 2DEC .0222222222 # = .5 DEG/SEC 018028,000074: 018029,000075: 22,2776 02660 13301 2DEC .0888888889 # = 2 DEG/SEC $22.5 DEG/SEC 018030,000076: 018031,000077: 22,3000 00003 04000 ANGLTIME 2DEC .000190735 # = 100B - 19 018032,000078: 018033,000079: # MANEUVER ANGLE TO MANEUVER TIME 018034,000080: 22,3002 03146 14632 QUADROT 2DEC .1 # ROTATION MATRIX FROM S/C AXES TO CONTROL 018035,000081: 018036,000082: # Page 413 018037,000083: 22,3004 00000 00000 2DEC 0 B-28 # AXES (X ROT = -7.25 DEG) 018038,000084: 018039,000085: 22,3006 00000 00000 2DEC 0 B-28 018040,000086: 018041,000087: 22,3010 00000 00000 2DEC 0 B-28 018042,000088: 018043,000089: 22,3012 03131 11275 2DEC .099200 # =(.1)COS7.25 018044,000090: 018045,000091: 22,3014 77461 47370 2DEC -.012620 # =-(.1)SIN7.25 018046,000092: 018047,000093: 22,3016 00000 00000 2DEC 0 B-28 018048,000094: 018049,000095: 22,3020 00316 30407 2DEC .012620 # (.1)SIN7.25 018050,000096: 018051,000097: 22,3022 03131 11275 2DEC .099200 # (.1)COS7.25 018052,000098: 018053,000099: 22,3024 00004 05253 BIASCALE 2DEC .0002543132 # = (450/180)(1/0.6)(1/16384) End of include-file GIMBAL_LOCK_AVOIDANCE.agc. Parent file is MAIN.agc