Flight Safety Assessment and Management.

[摘要] This dissertation develops a Flight Safety Assessment and Management (FSAM) system to mitigate aircraft loss of control risk. FSAM enables switching between the pilot/nominal autopilot system and a complex flight control system that can potentially recover from high risk situations but can be hard to certify. FSAM monitors flight conditions for high risk situations and selects the appropriate control authority to prevent or recover from loss of control. The pilot/nominal autopilot system is overridden only when necessary to avoid loss of control. FSAM development is pursued using two approaches. First, finite state machines are manually prescribed to manage control mode switching. Constructing finite state machines for FSAM requires careful consideration of possible exception events, but provides a computationally-tractable and verifiable means of realizing FSAM. The second approach poses FSAM as an uncertain reasoning based decision theoretic problem using Markov Decision Processes (MDP), offering a less tedious knowledge engineering process at the cost of computational overhead. Traditional and constrained MDP formulations are presented. Sparse sampling approaches are also explored to obtain suboptimal solutions to FSAM MDPs. MDPs for takeoff and icing-related loss of control events are developed and evaluated. Finally, this dissertation applies verification techniques to ensure that finite state machine or MDP policies satisfy system requirements. Counterexamples obtained from verification techniques aid in FSAM refinement. Real world aviation accidents are used as case studies to evaluate FSAM formulations. This thesis contributes decision making and verification frameworks to realize flight safety assessment and management capabilities. Novel flight envelopes and state abstractions are prescribed to aid decision making.

[发布机构] University of Michigan

[效力级别] Aerospace Information Systems

[关键词] Decision making for safe autonomous operation;Aerospace Information Systems;Aerospace Engineering;Engineering;Aerospace Engineering