Integrating 1553 Avionics Bus Hardware Into ELV Simulation

Integrating 1553 Avionics Bus Hardware Into ELV Simulation Model by Elias Victor for Florida Institute of Technology (FIT) School of Electrical and Computer Engineering (ECE) Master’s Thesis Committee 9/17/2020 by Elias Victor (6112) 1

Study Purpose l To integrate a MIL-STD-1553 avionics bus into an existing NASA Matlab/Simulink rocket launch simulation. l To show that the original simulation results can be duplicated using the 1553 integrated solution. l To give mission analysts the capability to test actual flight hardware and software. 9/17/2020 by Elias Victor (6112) 2

Choice Definitions l Simulink: along with Matlab, Simulink is a Mathworks, Inc. product that allows for the simulation, modeling and analysis of dynamic systems. Simulink is provided with an extensive library of blocks that can be used to simulate many common system behaviors, but also allows for the creation of your own custom blocks. l UCAT: Universal Controls and Analysis Tool l S-function: a custom Simulink block made up of function callbacks that are called at different times during simulation execution. l Triggered Subsystem: Simulink block that executes when a trigger event occurs. l 1553 Data Bus: a common avionics data bus composed of cables, couplers and terminators. l 1553 Word: a 16 -bit sequence plus sync and parity. l Bus Controller: terminal in charge of initiating message transfers on the 1553 bus. l Remote Terminal: terminal that operates as a slave on the 1553 bus servicing bus controller requests. 9/17/2020 by Elias Victor (6112) 3

Outline l l l Prototype Description Demo integrated 1553 simulation startup Integrated Components Control System Message Formats Message Exchange S-function Callbacks Hurdles Overcome Findings of Interest Further Study Possibilities Conclusion Results Comparison 9/17/2020 by Elias Victor (6112) 4

Prototype Description 9/17/2020 by Elias Victor (6112) 5

Demo Start integrated 1553 simulation. 9/17/2020 by Elias Victor (6112) 6

Integrated Components Original: Integrated Elements: 9/17/2020 by Elias Victor (6112) 7

Integrated Components Original: Integrated Elements: 9/17/2020 by Elias Victor (6112) 8

Integrated Components Original: Integrated Elements: 9/17/2020 by Elias Victor (6112) 9

Integrated Components Original: Integrated Elements: 9/17/2020 by Elias Victor (6112) 10

Integrated Components Original: Integrated Elements: 9/17/2020 by Elias Victor (6112) 11

Integrated Components Original: Integrated Elements: 9/17/2020 by Elias Victor (6112) 12

Control System (original) NOTE: Details of simulation blocks’ internals have been omitted for proprietary reasons. 9/17/2020 by Elias Victor (6112) 13

Control System (integrated) ucatrt = remote terminal ucatbc = bus controller NOTE: Details of simulation blocks’ internals have been omitted for proprietary reasons. 9/17/2020 by Elias Victor (6112) 14

Message Formats Sensor Reading: Delta Theta (3 doubles, 64 bits each) Delta Velocity (3 doubles, 64 bits each) Gyro Input (2 shorts, 16 bits each) Ground Input Discretes (2 shorts, 16 bits each) d = data, u = unused/reserved, cnt = count, csum = checksum 9/17/2020 by Elias Victor (6112) 15

Message Formats Commands Response: (36 shorts, 16 bits each) d = data, u = unused/reserved, cnt = count, csum = checksum 9/17/2020 by Elias Victor (6112) 16

Message Exchange 9/17/2020 by Elias Victor (6112) 17

Message Exchange 9/17/2020 by Elias Victor (6112) 18

Message Exchange 9/17/2020 by Elias Victor (6112) 19

Message Exchange 9/17/2020 by Elias Victor (6112) 20

Message Exchange 9/17/2020 by Elias Victor (6112) 21

Message Exchange 9/17/2020 by Elias Victor (6112) 22

Message Exchange 9/17/2020 by Elias Victor (6112) 23

S-function Callbacks 9/17/2020 by Elias Victor (6112) 24

Hurdles Overcome l Gathering prototype hardware and software l 1553 transmission racing conditions l Accelerated vs. Normal l SBS reference library correction l C compiler differences (VCC vs. LCC) 9/17/2020 by Elias Victor (6112) 47

Findings of Interest l Performance impact: l Average elapsed-times in real-time seconds based on 10 consecutive runs of each simulation: l l l 9/17/2020 Original simulation = 8, 768. 5 Integrated 1553 simulation = 9, 503. 1 Difference: 9503. 1 - 8768. 5 = 734. 6 Degradation: ( 734. 6 / 8, 768. 5 ) * 100% = 8. 4% Acceptable considering benefits by Elias Victor (6112) 48

Findings of Interest (continued) “accelerated” is NOT “normal” NOTE: actual yaw and pitch variables renamed to VAR 2 for proprietary reasons � 9/17/2020 by Elias Victor (6112) 49

Findings of Interest (continued) All compilers are NOT created equal. NOTE: actual yaw and pitch variables renamed to VAR 2 for proprietary reasons 9/17/2020 by Elias Victor (6112) 50

Further Study Possibilities l l Connect actual flight devices to simulation Reduce simulation elapsed-time to real-time or better: l l l Port to Linux with custom kernel Buy faster hardware Investigate use of The Mathworks, Inc. Real Time Workshop and/or x. PC Target products Integrate 1553 bus into other vehicle simulations (develop library of 1553 S-function blocks). Investigate why “accelerated” and “normal” modes generate different results. Investigate why different compilers generate different results. 9/17/2020 by Elias Victor (6112) 51

Conclusion l The 1553 bus was successfully added using the triggered subsystem and S-function capabilities of Simulink. l The results generated by the 1553 integrated simulation are exactly the same as those obtained by the original simulation. l The NASA KSC Mission Analysis Branch now has the ability to connect and test actual flight hardware and software in its simulation models. l I have learned about Matlab, Simulink, and 1553 communications. 9/17/2020 by Elias Victor (6112) 52

Show Results Comparisons 1. plot_compare(‘Analyst_orig. mat’, ‘ 1553_plant. mat’) 2. plot_compare_with_differences(‘UCATPLANT_orig. mat’, ‘UCATPLANT_orig_accel. mat’) 3. plot_compare_with_differences(‘Analyst_orig. mat’, ‘ 1553_VCC. mat’) 4. plot_compare_with_differences(‘Analyst_orig. mat’, ‘ 1553_LCC. mat’) 9/17/2020 by Elias Victor (6112) 53

Questions 9/17/2020 by Elias Victor (6112) 54