This paper focuses on the challenges of modeling cyber-physical systems (CPSs) that arise from the intrinsic heterogeneity, concurrency, and sensitivity to timing of such systems. It uses a portion of an aircraft vehicle management system (VMS), specifically the fuel management subsystem, to illustrate the challenges, and then discusses technologies that at least partially address the challenges. Specific technologies described include hybrid system modeling and simulation, concurrent and heterogeneous models of computation, the use of domain-specific ontologies to enhance modularity, and the joint modeling of functionality and implementation architectures.

Modeling Cyber–Physical Systems

The constant growth of air traffic, the demand for performance optimization, and the need for decreasing both operating and maintenance costs have encouraged the aircraft industry to move toward more electric solutions. As a result of this trend, electric power required on-board of aircraft has significantly increased through the years, causing major changes in electric power system architectures. Considering this scenario, this paper gives a review about the evolution of electric power generation systems in aircraft. The major achievements are highlighted and the rationale behind some significant developments discussed. After a brief historical overview of the early dc generators (both wind- and engine-driven), the reasons which brought the definitive passage to the ac generation, for larger aircraft, are presented and explained. Several ac generation systems are investigated with particular attention being focused on the voltage levels and the generator technology. Furthermore, examples of commercial aircraft implementing ac generation systems are provided. Finally, the trends toward modern generation systems are also considered giving prominence to their challenges and feasibility.

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Electrical Power Generation in Aircraft: Review, Challenges, and Opportunities

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 performance requirements. To reduce expensive redesign 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 implementation 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 toward 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.

A Contract-Based Methodology for Aircraft Electric Power System Design

This paper presents the recent advancements in the control of multiple-degree-of-freedom hydraulic robotic manipulators. A literature review is performed on their control, covering both free-space and constrained motions of serial and parallel manipulators. Stability-guaranteed control system design is the primary requirement for all control systems. Thus, this paper pays special attention to such systems. An objective evaluation of the effectiveness of different methods and the state of the art in a given field is one of the cornerstones of scientific research and progress. For this purpose, the maximum position tracking error $|e|_{\rm max}$ and a performance indicator $\rho$  (the ratio of $|e|_{\rm max}$ with respect to the maximum velocity) are used to evaluate and benchmark different free-space control methods in the literature. These indicators showed that stability-guaranteed nonlinear model based control designs have resulted in the most advanced control performance. In addition to stable closed-loop control, lack of energy efficiency is another significant challenge in hydraulic robotic systems. This paper pays special attention to these challenges in hydraulic robotic systems and discusses their reciprocal contradiction. Potential solutions to improve the system energy efficiency without control performance deterioration are discussed. Finally, for hydraulic robotic systems, open problems are defined and future trends are projected.

A Survey on Control of Hydraulic Robotic Manipulators With Projection to Future Trends

This paper presents an overview of technology related to on-board microgrids for the more electric aircraft. All aircraft use an isolated system, where security of supply and power density represents the main requirements. Different distribution systems (ac and dc) and voltage levels coexist, and power converters have the central role in connecting them with high reliability and high power density. Ensuring the safety of supply with a limited redundancy is one of the targets of the system design since it allows increasing the power density. This main challenge is often tackled with proper load management and advanced control strategies, as highlighted in this paper.

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On-Board Microgrids for the More Electric Aircraft—Technology Review

Fight control systems engine control systems fuel systems hydraulic systems electrical systems pneumatic systems envronmental control systems emergency systems helicopter systems advanced systems systems design and development avionics technology.

Aircraft Systems: Mechanical, Electrical, and Avionics Subsystems Integration, Third Edition

This third edition of Aircraft Systems represents a timely update of this highly successful and widely acclaimed work. Moir and Seabridge present an in-depth study of the general systems of an aircraftelectronics, hydraulics, pneumatics, emergency systems, and flight control to name but a fewthat transform an aircraft shell into a living, functioning, and communicating flying machine. Advances in systems technology continue to integrate systems and avionics, with aircraft support and flight systems increasingly controlled and monitored by electronics; the authors handle the complexities of these interactions in a straightforward and accessible manner that also enhances the books synergy with its two sister volumes, Civil Avionics Systems and Military Avionics Systems.

Aircraft Systems: Mechanical, Electrical, and Avionics Subsystems Integration

Introduction Military Roles Technology and Architectures Basic Radar Systems Advanced Radar Systems Electrooptics Electronic Warfare Communications and Identification Navigation Weapons Carriage and Guidance Vehicle Management Systems Displays Bibliography Glossary Index.

Military Avionics Systems

Introduction Avionics Technology Data Bus Networks System Safety Avionics Architectures Systems Development Electrical Systems Sensors Communications and Navigation Aids Flight Control Systems Navigation Systems Flight Deck Displays Military Aircraft Adaptations References Further Reading Introduction to Appendices Appendix A: Safety Analysis - Flight Control System Appendix B: Safety Analysis - Electronic Flight Instrument System Appendix C: Safety Analysis - Electrical System Appendix D: Safety Analysis - Engine Control System Simplified Example (all failure rates per flight hour) Index.

Ian Moir

Papers

Aircraft Systems: Mechanical, Electrical, and Avionics Subsystems Integration, Third Edition

Aircraft Systems: Mechanical, Electrical, and Avionics Subsystems Integration

Military Avionics Systems

Civil Avionics Systems

The Aircraft Systems