Slide 1 Flight Simulation – Ch 8 A Case Study in an Architecture for “Integrability” Boeing...
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Transcript of Slide 1 Flight Simulation – Ch 8 A Case Study in an Architecture for “Integrability” Boeing...
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/.
Before software - the Wallingford Improved Flight Trainer, 1942. From www.janusmuseum.org/flight/flight.htm .
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=JGyJqXJWkuY .
• Thursday– Present outcomes for Project 2– Turn in Thurs night (and HW 3 -
Yikes!)
“How to clean the Gherkin”
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)
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
Slide 5
Structural Model
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.
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
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
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
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
Slide 11
Modules
• Executive– Timeline Synchronizer– Periodic Sequencer– Event handler– Surrogate
• Connects air vehicle model to environment model
• Application– Subsystem controller– Controller children
Slide 12
Allocation of Functionalityto 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
Slide 13
Decomposition
• n-Square Charts– What “Partition 2” communicates with…
Partition 1 Inputs
Outputs Partition 2 Outputs
InputsPartition 3
Slide 14
Air Vehicle Model Domain
• An example…
Kinetics Group LoadsVehicle State
VectorVehicle Position
PowerAircraft
Systems GroupPower
Inertial State Loads Avionics GroupOwnship
Emissions
Atmosphere, Terrain, and
Weather
Environment Emitter Data
Environment Group
Slide 15
SummaryHow 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
Slide 16
Questions?