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14
A case study on reactive protocols for aircraft electric power distribution
- In Proc. IEEE Conference on Decision and Control
, 2012
"... Abstract — We consider the problem of designing a control protocol for the aircraft electric power system that meets system requirements and reacts dynamically to changes in internal system states. We formalize these requirements by translating them into a temporal logic specification language descr ..."
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Abstract — We consider the problem of designing a control protocol for the aircraft electric power system that meets system requirements and reacts dynamically to changes in internal system states. We formalize these requirements by translating them into a temporal logic specification language describing the correct behaviors of the system, and apply formal methods to automatically synthesize a controller protocol that satisfies system properties and requirements. Through an example, we perform a design exploration to show the benefits and tradeoffs between centralized and distributed control architectures. I.
An Aircraft Electric Power Testbed for Validating Automatically Synthesized Reactive Control Protocols
, 2013
"... Modern aircraft increasingly rely on electric power for subsys-tems that have traditionally run on mechanical power. The complexity and safety-criticality of aircraft electric power sys-tems have therefore increased, rendering the design of these systems more challenging. This work is motivated by t ..."
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Cited by 4 (2 self)
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Modern aircraft increasingly rely on electric power for subsys-tems that have traditionally run on mechanical power. The complexity and safety-criticality of aircraft electric power sys-tems have therefore increased, rendering the design of these systems more challenging. This work is motivated by the potential that correct-by-construction reactive controller syn-thesis tools may have in increasing the effectiveness of the elec-tric power system design cycle. In particular, we have built an experimental hardware platform that captures some key elements of aircraft electric power systems within a simplified setting. We intend to use this platform for validating the ap-plicability of theoretical advances in correct-by-construction control synthesis and for studying implementation-related challenges. We demonstrate a simple design workflow from
Counter-Strategy Guided Refinement of GR(1) Temporal Logic Specifications
"... Abstract—The reactive synthesis problem is to find a finitestate controller that satisfies a given temporal-logic specification regardless of how its environment behaves. Developing a formal specification is a challenging and tedious task and initial specifications are often unrealizable. In many ca ..."
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Abstract—The reactive synthesis problem is to find a finitestate controller that satisfies a given temporal-logic specification regardless of how its environment behaves. Developing a formal specification is a challenging and tedious task and initial specifications are often unrealizable. In many cases, the source of unrealizability is the lack of adequate assumptions on the environment of the system. In this paper, we consider the problem of automatically correcting an unrealizable specification given in the generalized reactivity (1) fragment of linear temporal logic by adding assumptions on the environment. When a temporal-logic specification is unrealizable, the synthesis algorithm computes a counter-strategy as a witness. Our algorithm then analyzes this counter-strategy and synthesizes a set of candidate environment assumptions that can be used to remove the counter-strategy from the environment’s possible behaviors. We demonstrate the applicability of our approach with several case studies. I.
Dynamic State Estimation in Distributed Aircraft Electric Control Systems via Adaptive Submodularity
"... Abstract — We consider the problem of estimating the discrete state of an aircraft electric system under a distributed control architecture through active sensing. The main idea is to use a set of controllable switches to reconfigure the system in order to gather more information about the unknown s ..."
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Abstract — We consider the problem of estimating the discrete state of an aircraft electric system under a distributed control architecture through active sensing. The main idea is to use a set of controllable switches to reconfigure the system in order to gather more information about the unknown state. By adaptively making a sequence of reconfiguration decisions with uncertain outcome, then correlating measurements and prior information to make the next decision, we aim to reduce the uncertainty. A greedy strategy is developed that maximizes the one-step expected uncertainty reduction. By exploiting recent results on adaptive submodularity, we give theoretical guaran-tees on the worst-case performance of the greedy strategy. We apply the proposed method in a fault detection scenario where the discrete state captures possible faults in various circuit components. In addition, simple abstraction rules are proposed to alleviate state space explosion and to scale up the strategy. Finally, the efficiency of the proposed method is demonstrated empirically on different circuits. I.
Temporal Logic Control of Switched Affine Systems with an Application in Fuel Balancing
"... Abstract — We consider the problem of synthesizing hier-archical controllers for discrete-time switched affine systems subject to exogenous disturbances that guarantee that the trajectories of the system satisfy a high-level specification expressed as a linear temporal logic formula. Our method buil ..."
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Abstract — We consider the problem of synthesizing hier-archical controllers for discrete-time switched affine systems subject to exogenous disturbances that guarantee that the trajectories of the system satisfy a high-level specification expressed as a linear temporal logic formula. Our method builds upon recent results on temporal logic planning and embedded controller synthesis. First, the control problem is lifted to a discrete level by constructing a finite transition system that abstracts the behavior of the underlying switched system. At the discrete level, we recast the problem as a two player temporal logic game by treating the environment driven switches as adversaries. The solution strategy for the game (i.e. the discrete plan) is then implemented at the continuous level by solving finite-horizon optimal control problems that establish reachability between discrete states and that compensate the effects of continuous disturbances. We also extend the earlier work by making efficient use of propositions in the temporal logic formula to drive the abstraction procedure and to facilitate the computation of continuous input at implementation time. An aircraft fuel system example is formulated; and solved using the proposed method. This sample problem demonstrates the applicability of the abstraction procedure and correct-by-construction controllers to regulate the fuel levels in multiple tanks during interesting operations like aerial refueling. I.
Pattern-Based Refinement of Assume-Guarantee Specifications in Reactive Synthesis
"... We consider the problem of compositional refinement of components’ specifications in the context of compositional reactive synthesis. Our solution is based on automatic refinement of assumptions and guarantees expressed in linear temporal logic (LTL). We show how behaviors of the environment and t ..."
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We consider the problem of compositional refinement of components’ specifications in the context of compositional reactive synthesis. Our solution is based on automatic refinement of assumptions and guarantees expressed in linear temporal logic (LTL). We show how behaviors of the environment and the system can be inferred from counter-strategies and strategies, respectively, as formulas in special forms called patterns. Instantiations of patterns are LTL formulas which hold over all runs of such strategies, and are used to refine the specification by adding new input assumptions or output guarantees. We propose three different approaches for compositional refinement of specifications, based on how much information is shared between the components, and demonstrate and compare the methods empirically.
Specification and Synthesis of Reactive Protocols for Aircraft Electric Power Distribution
, 2014
"... The increasing complexity of electric power systems leads to challenges in integration and verification. We consider the problem of designing a control protocol for an aircraft electric power system that meets a set of requirements describing the correct behaviors of the system and reacts dynamical ..."
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The increasing complexity of electric power systems leads to challenges in integration and verification. We consider the problem of designing a control protocol for an aircraft electric power system that meets a set of requirements describing the correct behaviors of the system and reacts dynamically to changes in internal system states. We formalize the requirements by translating them into a temporal logic specification language and apply game-based, temporal logic formal methods to automatically synthesize a controller protocol that satisfies these overall properties and requirements. Through a case study, we perform a design exploration to show the benefits and tradeoffs between centralized and distributed control architectures.
Acknowledgement
, 2002
"... This thesis was prepared at the Faculty of Biochemical Pharmacology in the University of ..."
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This thesis was prepared at the Faculty of Biochemical Pharmacology in the University of
Noname manuscript No. (will be inserted by the editor) Persistent Surveillance for Unmanned Aerial Vehicles Subject to Charging and Temporal Logic Constraints
"... the date of receipt and acceptance should be inserted later Abstract In this work, we present a novel method for au-tomating persistent surveillance missions involving multiple vehicles. Automata-based techniques are used to generate collision-free motion plans for a team of vehicles to satisfy a te ..."
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the date of receipt and acceptance should be inserted later Abstract In this work, we present a novel method for au-tomating persistent surveillance missions involving multiple vehicles. Automata-based techniques are used to generate collision-free motion plans for a team of vehicles to satisfy a temporal logic specification. Vector fields are created for use with a differential flatness-based controller, allowing vehicle flight and deployment to be fully automated according to the motion plans. The use of charging platforms with the vehi-cles allows for truly persistent missions. Experiments were performed with two quadrotors over 50 runs to validate the theoretical results.
1A Contract-Based Methodology for Aircraft Electric Power System Design
"... Abstract—In an aircraft electric power system, one or more supervisory control units actuate a set of electromechanical switches to dynamically distribute power from generators to loads, while satisfying safety, reliability and real-time perfor-mance requirements. To reduce expensive re-design steps ..."
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Abstract—In an aircraft electric power system, one or more supervisory control units actuate a set of electromechanical switches to dynamically distribute power from generators to loads, while satisfying safety, reliability and real-time perfor-mance requirements. To reduce expensive re-design steps, this control problem is generally addressed by minor incremental changes on top of consolidated solutions. A more systematic approach is hindered by a lack of rigorous design methodologies that allow estimating the impact of earlier design decisions on the final implementation. To achieve an optimal imple-mentation that satisfies a set of requirements, we propose a platform-based methodology for electric power system design, which enables independent implementation of system topology (i.e. interconnection among elements) and control protocol by using a compositional approach. In our flow, design space exploration is carried out as a sequence of refinement steps from the initial specification towards a final implementation by mapping higher-level behavioral and performance models into a set of either existing or virtual library components at the lower level of abstraction. Specifications are first expressed using the formalisms of linear temporal logic, signal temporal logic and arithmetic constraints on Boolean variables. To reason about different requirements, we use specialized analysis and synthesis frameworks and formulate assume-guarantee contracts at the articulation points in the design flow. We show the effectiveness of our approach on a proof-of-concept electric power system design. I.
