A knowledge-based system design/information tool for aircraft flightcontrol systems

Rotorcraft flight control systems present design challenges which often exceed those associated with fixed-wing aircraft. First, large variations in the response characteristics of rotorcraft result from the wide range of airspeeds of typical operation (hover to over 100 kts). Second, the assumption of vehicle rigidity often employed in the design of fixed-wing flight control systems is rarely justified in rotorcraft where rotor degrees of freedom can have a significant impact on the system performance and stability. Proposed herein is a methodology for the design of robust rotorcraft flight control systems utilizing Quantitative Feedback Theory (QFI'), a technique which accounts for variability in the dynamic response of the controlled element in the design of robust control systems. It was developed to address a Multiple-Input-Single-Output (MISO) design problem, but was extended to the address the Multiple-Input-Multiple-Output (MIMO) flight control system (FCS) design problem of a UH-60 Black Hawk Helicopter. Inherent conservatism in this design technique leads to limitations in its utility. A modified QFI' approach proved a viable method for designing robust MIMO flight control systems. An analysis of the two flight control system design methodologies is presented.

Control systems are often required to operate in the presence of saturation nonlinearities, such as actuator displacement and rate limiting. Whereas the occurrence of saturation may possibly be minimized by the choice of closed-loop bandwidth, the nonlinearities themselves are essentially unavoidable, and system performance and even stability can be compromised when the nonlinearities are encountered. To address this problem, a design technique for improving the performance of single-input, single-output feedback systems operating in the presence of saturation nonlinearities is presented. The technique allows application to unstable plants and is an extension of that previously discussed in the literature for stable plants. A simple design example is provided that demonstrates the applicability of the methodology to a case of actuator rate limiting. Introduction and Background EEDBACK design techniques that explicitly consider the pos- sibility of control saturation are receiving increasing attention in the literature. Optimal control strategies for regulators employing inequality constraints on control and state variables are well known. * Techniques that attempt to minimize the adverse effects of saturation are also well established, e.g., antiwindup controllers.2 Feedback systems designed to avoid saturation have been discussed.3 Nonlin- ear feedback controllers designed with the goal of improved perfor- mance with state and control saturation have also been described.4 Finally, linear feedback schemes to improve the performance of systems with saturation nonlinearities have been formulated.5 The research to be described here falls into the last category. In particular, the treatment of actuator saturation as a nuisance nonlin- earity is pursued. This implies that the system in question experi- ences saturation relatively infrequently and that a nominal control system design was obtained ignoring any nonlinear actuation ef- fects. Such is the case for many aircraft flight control systems in which actuator saturation, either displacement or rate, is a relatively rare occurrence. The rarity of such occurrences is not accidental since the performance requirements of control surface actuators are typically an important part of flight control system specifications. Nonetheless, flight control actuator saturations do occur, typically, with high-performance aircraft.68 When conditionally stable sys- tems are involved (e.g., statically unstable aircraft), the results can be catastrophic.9-10 The design technique to be pursued is an extension of that devel- oped by Horowitz 5'11'12 and in Refs. 13 and 14 briefly outlined in the next section. Attention is focused on single-input, single-output (SISO) systems. The design equations are presented next, and the Horowitz technique is extended to unstable plants. The internal sta- bility and input-output stability of the resulting design approach are then discussed, and a simple example is presented which demon- strates the design approach.

Purpose – The presented paper aims to describe the general idea, simulations and prototyping process of an assisting flight control system (FCS) for light sport aircraft (LSA). The proposed FCS framework is intended to simplify piloting, reduce pilot workload, and improve system's reliability and handling qualities of manual flying. Design/methodology/approach – Assisting flight control strategy integrates mechanical and digital FCS into a synergic platform, combining the high reliability of mechanical controls with the computation and actuation power introduced through a single line digital FCS. Concepts drawn from classical control theory along with flight envelope protection algorithms have been used throughout the design of the flight control laws. A prototype of the assisting FCS has been subjected to validation trials during series of hardware-in-the-loop simulations. Findings – Despite controversies between the pilots' perception of a modern aircraft and limitations imposed by the legacy airworthiness codes, it has been shown that a pilot assisting and workload reducing control system can be successfully implemented on board of a LSA while satisfying the expectations on a state-of-the-art equipment meeting required level of safety defined by the current legislation. Research limitations/implications – A transition between specific flight modes as well as nonlinearities in the FCS may lead to unfavorable and unpredictable forms of aircraft-pilot interactions. The number of accessible flight control modes should be therefore limited to the most significant ones. Practical implications – Sport aircraft are mostly flown by a single pilot, who could benefit from the pilot assisting FCS as the system has the potential to supervise the aircraft's safe operation in various flight conditions. Originality/value – Introducing an assisting FCS on board of a LSA through an innovative approach which utilizes hidden and unused resources of modern digital automatic FCSs while respecting the limitations imposed through the weight and cost sensitive nature of the LSA market.

Research on a Safety-Critical Architecture of Large Commercial Aircraft Fly-by-Wire Flight Control System

We review practical case studies of a developing method of highly reliable real-time embedded control systems using a CPU model-based hardware/software co-simulation. We take an approach that enables us to fully simulate a virtual mechanical control system including a mechatronics plant, microcontroller hardware, and object code level software. This full virtual system approach simulates control system behavior, especially that of the microcontroller hardware and software. It enables design space exploration of microarchitecture, control design validation, robustness evaluation of the system, software optimization before components design. It also avoids potential problems. The advantage of this work is that it comprises all the components in a typical control system, enabling the designers to analyze effects from different domains, for example mechanical analysis of behavior due to differences in controller microarchitecture. To further improve system design, evaluation and analysis, we implemented an integrated behavior analyzer in the development environment. This analyzer can graphically display the processor behavior during the simulation without affecting simulation results such as task level CPU load, interrupt statistics, and the software variable transition chart. It also provides useful information on the system behavior. This virtual system analysis does not require software modification, does not change the control timing, and does not require any processing power from the target microcontroller. Therefore this method is suitable for real-time embedded control system design, in particular automotive control system design that requires a high level of reliability, robustness, quality, and safety. In this study, a Renesas SH-2A microcontroller model was developed on a CoMET™platform from VaST Systems Technology. An electronic throttle control (ETC) system and an engine control system were chosen to prove this concept. The electronic throttle body (ETB) model on the Saber® simulator from Synopsys® and the engine model on MATLAB®/Simulink®simulator from MathWorks can be simulated with the SH-2A model using a newly developed co-simulation interface between MATLAB®/Simulink® and CoMET™. Though the SH-2A chip was being developed as the project was being executed, we were able to complete the OSEK OS development, control software design, and verification of the entire system using the virtual environment. After releasing a working sample chip in a later stage of the project, we found that such software could run on both actual ETC system and engine control system without critical problem. This demonstrates that our models and simulation environment are sufficiently credible and trustworthy.

There are many design methods for the multiloop control system, but a method to exactly evaluate the stability margin for multiloop control systems has not been established yet. It is very important for the designers to exactly know the stability margin of the flight control system, because it directly comes to bear on flight safety. Previous research has proposed the “-1/ξ locus” analysis method for the exact evaluation of the stability margin of multiloop flight control systems. -1/ξ is an open loop transfer function of multiloop control systems that is considered as an extension of that for single-loop control systems. In this paper, the relation between the response of the closed loop and the stability margin is considered by using the -1/ξ locus. Lateral-directional flight control system was taken for instance, important points to pay attention to use the -1/ξ locus method for designing the flight control system are presented.

Welcome to the DATE 08 Conference Proceedings. DATE combines the world's favourite electronic systems design conference and Europe's leading international exhibition for electronic design, automation and test, from system level hardware and software implementation right down to integrated circuit design. The DATE 08 event features a technical program with 77 sessions covering the latest developments in system design and embedded software, IC design/test methodologies and EDA tools, together with an exhibition with the leading EDA, silicon and IP providers showing their new products and services. Challenges that you all face or soon will face in your daily practice are the increasing design complexity of highly integrated systems, the introduction of reconfigurability and embedded software, and the control of power and variability in nanometer IC designs. All these issues will be addressed in this year's DATE event. For the 11th successive year DATE has prepared an exciting technical programme, with the help of the more than 400 members of the Technical Programme Committee, who dedicated their time to thoroughly review the 839 submissions in 37 topics, ranging from system level down to circuit design and covering all the most relevant application domains. The submissions are organised in 4 major areas: D --- Design Methods, Tools, Algorithms and Languages A --- Application Design T --- Test Methods, Tools and Innovative Experiences E --- Embedded Software After a thorough review and selection process (with an average of 5 reviews per paper), finally 198 regular papers were selected for presentation at the conference. Additionally, there are 46 Interactive Presentations that are organised in 5 IP sessions. Together with the invited special sessions (panels, embedded tutorials and hot topic sessions), this has resulted in a high-quality technical program. The technical program provides a wide but high-quality coverage of design, design automation and test topics, from the system level to the integrated circuit level. Compared with previous years, submissions in the Embedded Software track has increased by 50%, showing a clear trend towards a comprehensive system design focus with integrated hardware and software solutions. DATE has established itself firmly as a true Electronic System Design Conference. This year the conference is held in Germany, at the ICM in Munich and spans an entire working week from Monday March 10 to Friday March 14. On Monday, eleven pre-conference tutorials will be given. The three-full day tutorials cover topics of great interest for system design. The first tutorial deals with techniques to automatically realising embedded system from high-level functional models. The second tutorial addresses the different issues related to communication based design and architectures in automotive electronic systems. The third tutorial discusses several key concepts on system-level design and application mapping for wireless and multimedia MPSoC architectures. Furthermore, eight half-day tutorials are also given, which cover a wide spectrum of topics on specification, modelling, design and test. The main conference opens on Tuesday March 11, with two very interesting and complementary keynote speeches. Dominique Vernay, Chief Technical Officer for Thales, will talk about the challenges of embedded systems design, and Giovanni de Micheli, Professor at EPFL, will present his views on designing micro/nano systems for a safer and healthier tomorrow. On the same day, the Executive Track offers a series of business panels with executives discussing hot topics in design: the perils of 45 nanometers, the changes in EDA strategies from IDM, to fablite to fabless, and embedded systems level design strategies. DATE 08 will again offer two specific days related to special themes. On Wednesday March 12, a special full-day track is devoted to Automotive Electronics---Software and Architecture. This special-day track will focus on the challenges faced by the automotive supply chain with particular attention to system and software architecture design. It provides a comprehensive analysis of the evolution of automotive architectures, including ECUs, sensors and communication standards and discusses how new methods, tools and standards for interoperability and component-based design can deal with the increasing complexity of software systems and their need for reliability and guaranteed timely behaviour. In addition, it addresses to what degree existing standards, including AUTOSAR and FLEXRAY and model-based development, can support the development of safety and time-critical software. On Thursday March 13, a second special full-day track focuses on Dependable Embedded Systems. This track will address both conceptual and applied issues for design, analysis and validation of dependable embedded systems. The utility of embedded systems and services is based, in large part, on our depending on their sustained functionality in spite of the encountered operational or malicious disruptions. As the number of transient and also permanent disruptions (given the decreasing device geometries, higher device density, lower voltage latching, faster clocks etc) is expected to increase substantially, this will not only be a key issue for the hardware community but also the systems community in general. Solutions using a combination of hardware and software might be more effective than hardware-only or software-only solutions. This track focuses on both conceptual and applied issues for design, analysis and validation of dependable embedded systems. Besides these special tracks, the main conference is organized in six parallel tracks of sessions, three devoted to design methods, tools, algorithms and languages, one to application design, one to test methods, tools and innovative experiences, and finally one to embedded software. The presentations of the selected regular papers in these parallel tracks are complemented by nine Special Sessions and two Invited Industrial Sessions. The special sessions are organized in the form of panels, hot topics, and embedded tutorials. The topics to be covered include quantitative evaluation for embedded systems design, design and manufacturing at 32 and 22nm, software for wireless networked embedded systems, test challenges for low power devices, quantitative productivity measurement in IC design, and 3D Integration. The two invited industrial sessions deal with industrial system designs in transportation and information technologies. To emphasise that DATE is the major event for the designers, DATE 08 features also invited sessions where Europe's famous consumer industry presents their best designs and design practices. Friday March 14 is the day for the DATE workshops. DATE 08 offers workshops on current and emerging important issues in design, test, EDA and software to complement the regular conference. They provide a unique opportunity for the various research and design communities to spend a day discussing the latest and the best, sharing their experiences and visions. This year's workshop program includes eight workshop themes. Four workshops are related to software engineering, ranging from dependable software to modelling, analysis and development tools. Four other workshop themes cover a variety of topics such as the impact of process variations on design and test, the merging world of Nano-Electro-Mechanical Systems, new directions in high level synthesis, and heterogeneous reconfigurable hardware. Each workshop features presentations, invited or submitted, from highly distinguished academic and industrial researchers. Finally, throughout the conference days, DATE offers a comprehensive overview of commercial design and verification tools in its large exhibition hall. Exhibitors include EDA vendors, silicon, FPGA and IP providers showing their new products and services. In addition, there is an Exhibition Theatre featuring talks from engineering managers of the leading electronic manufacturers on first-hand design experiences of commercial EDA tools. New this year is the European projects village where different European and large government funded projects will be able to show their ongoing research and results to the design community and have the opportunity for internal meetings and discussions. The DATE week will be also an opportunity for students and universities to show their research work, through the PhD Forum on Monday evening and the University Booth where hardware and software demonstrations will be shown by different universities on a rotation schedule. The DATE 08 event's program will be particularly attractive to industrial designers, at analog, IC, FPGA and embedded system level, as well as software designers, to researchers and academics as well as to design managers, and an increasing attendance is expected. We therefore invite you to take full advantage of the many opportunities offered to you by DATE 08, to extend your knowledge and/or business in electronic system's design and to exploit the abundant networking possibilities offered to socialise with colleagues, including fringe meetings and a memorable social party with bands and dancing. We hope that you will all enjoy the DATE 08 Conference and Exhibition.

The paper is devoted to the structural – parametrical design of the control systems for unmanned aerial vehicles. The structural – parametrical design of control systems was carried out with use of the separation theorem. The optimum law of control with use of Kalman filter and the optimum deterministic regulator was synthesized. The technique of simplification of obtained solution for the purpose of a possibility of its realization in the simple onboard computer is performed. Aforementioned synthesis procedure was applied for design of unmanned aerial vehicles autopilots with limited amount of the navigation sensors in presence of stochastic disturbances. The aerodynamic coefficients that compose the stat space matrices and used for synthesis are obtained via DATCOM software application

Although many information systems (IS) design methods and techniques are available to IS professionals, none of them completely supports the design process. One of the problems is that there is a mismatch between IS design method; and the system to be built. Actually, in designing an IS, the methods or techniques employed should match the types and characteristics of the system to be built. Thus paper will explore the relationship between IS types/characteristics and systems design methods, and provide IS designers with a systems framework to develop methods or techniques that match the types and characteristics of IS.

In the modern aviation field, flight control systems’ reliability and safety are paramount. This paper presents a triplex redundant flight control system based on the M1394B bus and designs several key algorithms to enhance system performance. Firstly, a triplex redundant flight control system with a redundant bus structure is constructed based on the characteristics of the M1394B bus. Secondly, a periodic synchronization algorithm with automatic adjustment capabilities is designed to achieve periodic synchronization among the Vehicle Management Computers. An improved voting algorithm based on a sliding window is proposed to enhance the decision-making accuracy and reliability of the control commands output by the flight control system. Additionally, a system reconstruction algorithm is designed to promptly identify and isolate faults, enabling the recovery and reallocation of system resources. Finally, experiments validate the effectiveness of the synchronization algorithm, voting algorithm, and system reconstruction algorithm. The results indicate that the system can effectively address practical engineering challenges and significantly improve reliability and stability. This research provides an essential theoretical foundation and practical reference for the design of future flight control systems for unmanned aerial vehicles and aircraft, holding significant relevance to application.

This book provides information covering the fundamentals of control theory and optimization applied to real-world flight control systems. Covers the following topics: the challenges inherent in flight control system design; an overview of their core approach to flight control system design utilizing multiobjective parametric optimization; the specific software developed called Control Designer’s Unified Interface (CONDUIT); detailed explanations of the tools, plots, language, and four key components involved in defining the problem using CONDUIT; the XV-15 hover/forward flight case study is discussed in sufficient detail for even seasoned veterans to find the presentation informative and useful. Here the authors have done an excellent job of demonstrating many flight control concepts; proprietary specifications; methodologies for developing simulation models of model-based flight control system designs; design of flight control systems; the inner workings of the design optimization approach. The coverage includes specifics of various algorithms, along with their relative advantages and disadvantages. This chapter also provides insights into sequential loop closure strategies, with emphasis on their effectiveness and practical use; nested versus simultaneous multiloop strategies; and design considerations for real-world applications. This book serves as an excellent reference for senior undergraduate and/or graduate students, and it provides a wellbalanced perspective covering the theory, implementation, and practical applications of flight control design.

Purpose: This study aims to design the flow of the e-budgeting system to develop the village financial system, as well as to increase transparency and accountability of the web-based budget system and minimize the occurrence of corruption loopholes in the village. Method: The design system uses the waterfall method to analyze a model systematically. The model development step starts with the design of the system, database, menu structure, and interface. The design of the e-budget information system is built using PHP and MySQL programming in the form of web-based applications. Results: This study developed a web-based e-budgeting application using the waterfall method to manage village finances. The online system increases flexibility, allowing access from any device. It runs smoothly on computers, with all menus functioning as designed, and is expected to simplify village financial management. Limitations: The researchers’ capability in designing the system is not optimal, as the researchers do not have the basis of informatics engineering, so the results obtained and delivered are not too detailed. Contributions: This system is expected to be useful to facilitate the process of financial management at the village government level. Novelty: The novelty of this study lies in the design of a village e-budgeting system with features like automatic Standard Unit Price calculation, automated tax management, and tracking of village income (PADes) for transparency. This application aims to enhance financial management, ensuring transparency and accountability in the village.

PurposeThe purpose of this paper is to study the control strategy of transition mode of the stopped-rotor (SR) aircraft under the condition of redundant control and complex aerodynamic characteristics.Design/methodology/approachThis paper first proposes a transition strategy for the conversion between helicopter mode and fixed-wing mode. Then, aiming at the redundancy of the two control systems in the transition process, a control model is proposed, which greatly simplifies the control in conversion mode. Then, to facilitate the design of the control system, the Takagi-Sugeno model of the SR aircraft in transition mode is established. Finally, an explicit model tracking and tuning parameter stability augmentation control system is designed, so that the SR aircraft has a good stability during the transition process. Then, the outer loop control system of transition flight is designed.FindingsThe simulation results show that the control strategy proposed in this paper can realize the mode conversion well. It lays a solid foundation for the subsequent engineering flight test for the SR aircraft.Originality/valueThe work done in this paper provides ideas and methods for the flight control system design of SR aircraft in transition mode. The method of designing control model to solve the coordination of redundant control system is also applicable for other multimode aircraft, which provides a simple and convenient method for the multimode aircraft control.

AUTONOMOUS FLIGHT CONTROL AND HARDWARE-IN-THE-LOOP SIMULATOR FOR A SMALL HELICOPTER

Not so long ago, research in flight control was largely an algorithmic endeavor???-???the objective was to devise higher performance control laws. Such research still continues, but an additional imperative is now prominent. For many new flight control developments, the challenge is not so much to come up with the control algorithm; the existing literature describes how to do that sufficiently well. The new challenges are cost-efficiency and development time reduction. This chapter revises some of the basic technology for flight control systems and discusses how computational tools are now being used to ensure that new control systems can be affordably developed and deployed. The target vehicles for the flight control technology described are military aircraft and missiles. There are notable differences between the two, such as the use of different sets of actuators (in missiles, for example, reaction jets can directly control roll, pitch, and yaw). Flight control system design requirements also differ fundamentally for aircraft and missiles,due to the presence of a pilot in the former. As a consequence, control techniques can differ. Dynamic inversion???-???a form of feedback linearization???-???is a popular technique for aircraft flight control, whereas linear quadratic optimal control is commonly used for missiles. In either case, complications arise due to the fact that accelerometers and gyros are not located at the center of gravity of the vehicle. In some cases, performance and stability can be improved by appropriately locating the sensors. Simulation and analysis software is now essential for flight control design. The chapter discusses tools within the MATRIXx toolset that permit performance and robustness evaluation over a range of operating conditions. Today's tools allow aerospace engineers to graphically design a flight control s ystem, analyze its performance and stability, and generate autocode that can be ported directly to training simulators, hardware in the loop simulators, and the aircraft itself. Similar tools are in use in other industries too-see Ch. 15 for an automotive industry perspective. Further discussion on computer aided control system design can also be found in Ch. 3 which also outlines a flight control application. What lies ahead for flight control? This chapter concludes by noting the interest in, and the challenges associated with, uninhabited aircraft. This topic is also discussed in Ch 10 where focus is on multi-vehicle aerospace challenges.