Flight Simulation Ch 8

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Flight Simulation Ch 8
Boeing 747 flight simulator in action from
http//www.bornrich.org/entry/plane-fanatic-builds
-30k-boeing-747-flight-simulator-in-his-bedroom/.

• A Case Study in an Architecture for
  Integrability

Before software - the Wallingford Improved Flight
Trainer, 1942. From www.janusmuseum.org/flight/fl
ight.htm .
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Coming Up

• Today
• When are the case study talks Now on course
  schedule and team spreadsheet
• Term paper - Intro
• Ch 08 Flight Simulation this ?
• Intro see for example YouTube vids
  http//www.youtube.com/watch?vJGyJqXJWkuY .
• Monday
• Present outcomes for Project 2
• Turn in Mon night (and HW 3)

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Overview

• Structural Model
• Minimize modules
• N-Square charts
• Requirements and Qualities
• Three roles
• Lots of constraints
• Architectural Solution
• Treatment of time (real-time)

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Pattern - Structural Model

• Simplicity and similarity of the systems
  substructures
• Decoupling of data- and control-passing
  strategies from computation
• Minimizing module types
• A small number of system-wide coordination
  strategies
• Transparency of design

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Structural Model
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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 ones not one of ours?
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Requirements and Qualities

• Real-time performance constraints
• Continuous development and modification
• Large size and high complexity
• Developed in geographically distributed areas

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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

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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

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Architectural Solution, cntd

• Structural Model Architectural Pattern
• Executive
• Handles the coordination issues
• Application
• Handles computation of the simulation
• Functions are implemented by subsystems

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Modules

• Executive
• Timeline Synchronizer
• Periodic Sequencer
• Event handler
• Surrogate
• Connects air vehicle model to environment model
• Application
• Subsystem controller
• Controller children

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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

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Decomposition

• n-Square Charts
• What Partition 2 communicates with

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Air Vehicle Model Domain

• An example

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Summary

• How the architecture achieves
• Performance
• Executive with time budgets, and
• Periodic scheduling strategy
• Integrability
• All data and control pass through a subsystem
  controller
• Modifiability
• Few base module configurations for the designer
  and maintainer to understand

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Questions?