1. Slide 1 Flight Simulation – Ch 8 A Case Study in an Architecture for “Integrability” Boeing 747 flight simulator in action – from http://www.bornrich.org/entry/plane-fanatic-builds-30k- boeing-747-flight-simulator-in-his-bedroom/. http://www.bornrich.org/entry/plane-fanatic-builds-30k- boeing-747-flight-simulator-in-his-bedroom/ Before software - the Wallingford Improved Flight Trainer, 1942. From www.janusmuseum.org/flight/flight.htm.www.janusmuseum.org/flight/flight.htm

2. Slide 2 Coming Up Today… –Term paper - Intro –Ch 08 – Flight Simulation – this  Intro – see for example YouTube vids: http://www.youtube.com/watch?v=JGyJ qXJWkuY. http://www.youtube.com/watch?v=JGyJ qXJWkuY Thursday –Present outcomes for Project 2 –Turn in Thurs night (and HW 3 - Yikes!) “How to clean the Gherkin”

3. Slide 3 Overview Structural Model –Minimize modules N-Square charts Requirements and Qualities –Three roles –Lots of constraints Architectural Solution –Treatment of time (real- time)

4. Slide 4 Pattern - Structural Model Simplicity and similarity of the system’s substructures Decoupling of data- and control-passing strategies from computation Minimizing module types A small number of system-wide coordination strategies Transparency of design

5. Slide 5 Structural Model

6. Slide 6 Roles The Crew –The people being trained The Simulator Instructor –Monitors crew performance –Initiates training situations The Environment –Atmosphere, threats, weapons, other aircraft “Maybe that one’s not one of ours? Modern simulator from the outside.

7. Slide 7 Requirements and Qualities Real-time performance constraints Continuous development and modification –Maintains “verisimilitude” = realism, as the airplanes changed specs Large size and high complexity Developed in geographically distributed areas

8. Slide 8 Problems Expensive to debug, test, and modify –Increased cost of integration Unclear mapping between software structure and aircraft structure –Many coupling effects to be considered E.g., pilot moves the rudder and aileron controls, which move the control surfaces, which affects the aerodynamics and causes the aircraft to turn. –Performance “fidelity” is # 1 goal

9. Slide 9 Architectural Solution Treatment of Time Periodic time management –A fixed time quantum based on frame rate –Non-preemptive cycle scheduling – invokes each process for a fixed time quantum Event-based time management –“Interrupt” based –Adds new events into event queue –Does in order of soonest needed But all messages from a single source must be done in order! Mixed-time systems –The two above systems must interact

10. Slide 10 Architectural Solution, cntd Structural Model Architectural Pattern Executive –Handles the coordination issues Application –Handles computation of the simulation –Functions are implemented by subsystems

11. Slide 11 Modules Executive –Timeline Synchronizer –Periodic Sequencer –Event handler –Surrogate Connects air vehicle model to environment model Application –Subsystem controller –Controller children

12. Slide 12 Allocation of Functionality to controller children Based on OO modeling of the “objects” of the real airplane: Kinetics – the physics Aircraft systems – distribution of energy within the airframe Avionics – ancillary support Environment

13. Slide 13 Decomposition n-Square Charts –What “Partition 2” communicates with… Partition 1Inputs OutputsPartition 2Outputs Inputs Partition 3

14. Slide 14 Air Vehicle Model Domain An example… Kinetics GroupLoads Vehicle State Vector Vehicle Position Power Aircraft Systems Group Power Inertial StateLoadsAvionics Group Ownship Emissions Atmosphere, Terrain, and Weather Environment Emitter Data Environment Group

15. Slide 15 Summary How the architecture achieves… Performance –Executive with time budgets, and –Periodic scheduling strategy Integrability –All data and control pass through a subsystem controller as an intermediary –Each partition was restricted in inputs and outputs Modifiability –Few base module configurations for the designer and maintainer to understand

16. Slide 16 Questions?