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In see-through helmet-mounted displays (HMDs), image-intensifier tubes are located on the sides of the helmet. This HMD design increases the effective interpupillary distance and exposes the observer to hyperstereopsis. The modification of three-dimensional space perception by hyperstereopsis in laboratory studies is well known. Little is known, however, about its effects in real, operational conditions. The present study investigated the effects of hyperstereopsis on visual perception in helicopter pilots during the first flight of a night-flight training program using a see-through HMD. Fifteen pilots’ percepts of distance and height under hyperstereoscopic viewing were assessed using a double-distance estimation task in standard flight circuits. In addition, two questionnaires were used to characterize the perceptual effects induced by hyperstereoscopic viewing during the first night flight, and to determine whether any aftereffects were still present during the 24-h period following the flight. Height and distance estimation errors were observed. On average, pilots tended to underestimate the near plane relative to the farther plane in the double-distance estimation task; this is the inverse of what is commonly observed under natural viewing. We ascribed this effect to a non-linear decrease in the hyperstereopsis effect with viewing distance. Six pilots experienced sensory illusions resembling a distortion of apparent visual space: the impression of “sinking into a hole” when landing, of objects appearing closer than they actually were, and reduced in size. Four pilots cited landing as the most difficult situation encountered during the flight. Only minor complaints were reported for the 24-h period following the flight. The results of this field study represent a step towards characterizing the perceptual and operational impact of this display technology in helicopter pilots during initial exposure. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicles are widely spread and intensively used ones both in governmental and in private applications. The standard arrangements of the commercial-off-the-shelves unmanned aerial vehicles sometimes neglect application of the automatic flight control system onboard. However, there are many initiatives to ensure autonomous flights of the unmanned aerial vehicles via pre-programmed flight paths. Moreover, automatic flight control system can ensure necessary level of the flight safety both in VFR and IFR flights. The aim of this study is to guide UAV users in set up commercial onboard autopilots available on the market. On the contrary, fitness of the autopilot to a given type of the air robot is not guaranteed, and, an extra load on users can appear in controller settings. The proposed pole placement technique is one of the proper methods eliminating difficulties, and, computer aided gain selection using MATLAB will be presented. [ABSTRACT FROM AUTHOR]

The paper presents the design of a symmetric, active, gust load alleviation system for a regional transport aircraft, based on a static output feedback with a constrained structure. The design is carried out on a comprehensive finite state aeroservoelastic model, including sensor units and actuator transfer functions, and verified by taking into account saturated control positions, rates, and hinge moments. The controller is designed within a quadratic optimal framework, through a second-order Hessian-based optimization algorithm, exploiting block diagonal Schur transformations of the closed-loop state equations and performance weightings. An accurately chosen worst discrete gust and a reference flight condition provide a baseline design, which is significantly effective in alleviating continuous turbulence loads. Such a reference design proves itself robust enough to alleviate atmospheric loads over the complete flight envelope and is eventually further improved and robustified through a simple bilinear q∞- M∞ algebraic scheduling. [ABSTRACT FROM AUTHOR]

Abstract. Comparative analysis of the ICAO statistics showed that 35% of the aircraft losses associated with failures and damages of automatic control systems, mainly with failures of drives and external damage of tours and controllers. Classification of approaches to reconfigurable flight control systems is shown. The aim of this work is to develop method of reconfiguration to save the stability and controllability of the aircraft during the collisions with mechanical, biological and electrical elements. [ABSTRACT FROM AUTHOR]

The article analyses new trends in aircraft control under instrument flight rules. It describes the possibilities of using conventional area navigation methods with GNSS devices in approach phase. The authors describe the actual possibilities of using GNSS, especially GPS system, during navigation. In the next part, arrival and departure RNAV routes that are actually in use are described. The article also discusses briefing and preparation for RNAV approaches and describes requirements for the aircrew. [ABSTRACT FROM AUTHOR]

Abstract: Japanese Venus Climate Orbiter/AKATSUKI was proposed in 2001 with strong support by international Venus science community and approved as an ISAS (The Institute of Space and Astronautical Science) mission soon after the proposal. The mission life we expected was more than two Earth years in Venus orbit. AKATSUKI was successfully launched at 06:58:22JST on May 21, 2010, by H-IIA F17. After the separation from H-IIA, the telemetry from AKATSUKI was normally detected by DSN Goldstone station (10:00JST) and the solar cell paddles’ deployment was confirmed. After a successful cruise, the malfunction happened on the propulsion system during the Venus orbit insertion (VOI) on Dec. 7, 2010. The engine shut down before the planned reduction in speed to achieve. The spacecraft did not enter the Venus orbit but entered an orbit around the Sun with a period of 203 days. Most of the fuel still had remained, but the orbital maneuvering engine was found to be broken and unusable. However, we have found an alternate way of achieving orbit by using only the reaction control system (RSC). We had adopted the alternate way for orbital maneuver and three minor maneuvers in Nov. 2011 were successfully done so that AKATSUKI would meet Venus in 2015. We are considering several scenarios for VOI using only RCS. [Copyright &y& Elsevier]

Purpose -- The paper aims to detail the educational flight testing activities performed at the Department of Aerospace Science and Technology at the Politecnico di Milano (DSTA-PoliMi), including the development of low-cost, reliable flight testing instrumentation (FTI) and the administration of the graduate course in flight testing. Design/methodology/approach -- The flight testing course program closely adheres to the typical content of an introductory course offered in a professional flight testing school. However, within academic courses, it has a unique feature: each student is required to plan, perform and report on a real flight test experience, acting as a flight test engineer. Educational activities in this framework have been successfully matched to applied research and technical support for private companies. Findings -- At the educational level, several elements arise that are rarely concentrated within a single course, such as multidisciplinary integration, individual conceive-design-implement-operate (CDIO) project, real-life experimental procedures and techniques, teamwork, communication and reporting, relation with non-academic partners. Practical implications -- Based on the development of a FTI system for light aviation and on the flight testing course, DSTA-PoliMi has built a solid capability in flight testing, introducing graduate students to this specific niche of expertise and empowering co-operation with companies in the light aviation environment, while offering capabilities and tools that are typically regarded as a prerogative of major aerospace companies. Originality/value -- The paper discusses an original approach to flight testing education in an academic setting that avoids the high costs and complexity connected to certified aircraft flight operations and instrumentation, nevertheless allowing the achievement of significant results, also in applied engineering research. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to develop an attitude control strategy for the reusable boosted vehicle with large angle of attack, and to remove the cross coupling among roll, pitch and yaw channels. Design/methodology/approach – The coordinated gain scheduling control strategy consists mainly of two parts. First, initially ignoring dynamic coupling, single channel gain scheduling controller is designed based on linearized models, respectively. Second, with respect to main channel gain scheduling controller, coordinated scheduling controller is used to generate intentionally cross coupling to partly cancel inter-channel cross coupling of reusable boosted vehicle. Findings – A coordinated gain scheduling control strategy is presented, and no such analytical solution can be found for the reusable boosted vehicle. Practical implications – The design idea of coordinated gain scheduling strategy is straightforward in physical concepts and has great value for engineering applications. Originality/value – Coordinated gain scheduling control strategy is novel in that single channel gain scheduling design does not involve small perturbation linearization and coordinated channel is scheduled. [ABSTRACT FROM AUTHOR]

During an operational process, activity is implemented through an ordered sequence of certain actions united by a common motive. Actions can be simple or complex. Simple actions cannot be split into elements having independent objectives. Complex actions can be presented in the form of a set of simple actions. If the logical organisation of this set is open, a complex action can be described as an algorithm consisting of simple actions. That means various kinds of operational activities develop from the same simple and typical actions, but in various sequences. Therefore, human error is always generated by a more elementary error of action. Thus, errors of action are the primary parameter that is universal for any kind of activity of an aviation specialist and can serve as a measure for estimating the negative influence of the human factor (HF) on flight safety. Aviation personnel are various groups of experts having various specialisations and working in various areas of civil aviation. It is obvious that their influence on conditions is also unequal and is defined by their degree of interaction with the performance of flights. In this article, the results of an analysis of air incidents will be presented. [ABSTRACT FROM AUTHOR]

Abstract: Airships provide an attractive solution to many challenges in the aviation industry. The buoyancy force offered by the airship enables to be used for long endurance aero applications. Key objective is to operate the vehicle with a sufficient level of autonomy under extreme range of atmospheric and wind conditions. In order to achieve these goals, a guidance and control system is needed which controls the airship in air at the specified height. The accurate control system first requires an accurate model of the airship dynamics. Based on six degrees of freedom, an airship dynamic model is presented in this paper. The aerodynamic part of the model is taken from the geometrical configuration of the vehicle instead of expensive wind tunnel test setup. The computer simulation algorithm is then derived and the easily available Matlab environment is used to simulate it and its initial validation for YEZ-2A airship is demonstrated. [Copyright &y& Elsevier]

Abstract: Pure gravity orbit is an orbit removed non-gravity disturbances, which can give a more precise relation between gravity and orbit, and can be used to navigation satellite, earth gravity felid measurement, gravity wave detection and other fundamental physical test mission. In this paper, the author propose a system concept of a new pure gravity orbit acquirement method named inner formation flying system, which treats the PM and the outer satellite as a pair of formation flying satellites. The inner formation flying system consists of an outer satellite and an inner satellite. The outer satellite is a small satellite with a cavity in the center. The inner satellite is a PM flying in the housing of the outer satellite''s cavity. So the inner satellite is shielded from non-gravitational forces of atmosphere drag and radiation pressure and flies along a purely gravitational path. From the view of formation flying, the outer satellite can be treated as a formation satellite with zero or small distance to the inner reference satellite. So the analysis of mechanic and dynamics of inner formation is made at first. Then a control architecture including feed forward and feedback strategies is presented and the controller is designed. The simulation is carried out in a high precision formation flying simulation environment at last to validate the inner formation flying methods. [Copyright &y& Elsevier]

Abstract: Three satellites in formation flying have the flexibility to monitor the target on the ground and the vicinity in the space, and can even achieve stereo view for any object. We consider each satellite orbit is slightly different with a daily-repeat circular Sun-synchronous orbit in the inclination, the right ascension of ascending node, the argument of perigee, and the mean anomaly. According to the linearized orbit equation, a formation of a tilted triangle with respect to the equatorial plane can be constructed. A Sun-synchronous formation is then obtained through a rotation. We investigate the maintenance cost through the evaluation of the delta-V for the triangle formation under perturbation by the PID autonomous control of the nonlinear equation of motion. With reference to the relative position with respect to the formation centroid, the formation configuration can be maintained with less delta-V. [Copyright &y& Elsevier]

The paper briefly overviews the application of membrane and jet pneumatic devices in control systems. The most promising lines of development in the field are discussed. [ABSTRACT FROM AUTHOR]

This paper describes calculations and computer simulations concerning handling qualities of general aviation aircraft equipped with an indirect (fly-by-wire) control system. The main idea of this proposal is shaping small aircraft dynamic characteristics in a way that enables all general aviation aircraft to exhibit similar user-friendly properties from the pilot's point of view. The natural solution of this problem is modifying aircraft dynamic properties to comply with the 'ideal model' of a safe and easily controllable airplane. We can improve the handling qualities of an aircraft using the indirect flight control system. In this paper, the model following method was used for controller synthesis, with the purpose of obtaining qualitatively new handling properties and simplifying the control system for pilots with limited professional training. However, a control system designer has to assume responsibility for proper functioning of complex flight control systems. The properties of the optimal controller were calculated applying the indirect (implicit) model following method. In particular, the modified version based on the computer simulations was used. Model following method allows shaping properties of the flight control systems that satisfactorily approximate those of the desired model of controlled aircraft. In this way, the expected handling qualities can be reached. [ABSTRACT FROM AUTHOR]

A concept for lift modification on a conventional aircraft wing flow roll control at low angle of attack with dielectric barrier discharge plasma actuators is proposed and assessed through computational fluid dynamics simulations and preliminary wind-tunnel experiments. The concept consists of placing plasma actuators around the wing tip to add momentum in the direction opposite to that of the flow forming the tip vortex. Because of the limited strength of existing plasma actuators, the assessment is carried out for a relatively small two-dimensional wing (NACA 4418) with a rounded tip at zero angle of attack and 15 m/s for a Reynolds number in the range of 1.5 x 105. Computational fluid dynamics simulations show a significant alteration of the vorticity field downstream of the trailing edge characterized by a more diffused vortex surrounded by zones of negative vorticity induced by the actuators and, but not necessarily, outboard displacement of the tip vortex. This leads to a reduced downwash that results in a change in lift of up to almost 20% for actuator strength levels that should be achievable in the short term with a new generation of dielectric barrier discharge actuators. The actuator placed on the suction side contributes the most to the lift increase, with its induced jet blocking the flow around the wind tip at the origin of the formation of the tip vortex. Wind-tunnel experimental results support the computational fluid dynamics predictions in both magnitude and trend. Furthermore, preliminary computational fluid dynamics simulations are carried out for a symmetric nonlifting wing (NACA 0018), representative of aircraft tail surfaces at zero angle of attack to generate lift for pitch and yaw control. Results indicate lift generation that increases and becomes larger than drag at higher actuator strengths. These promising results show a potential for the proposed concept to replace movable flight control surfaces on future aircraft wings and empennages. [ABSTRACT FROM AUTHOR]

This paper presents the vertical takeoff, landing and transition between level flight and hovering of a tail-sitter vertical takeoff and landing (VTOL) aerial robot. The tail-sitter is suitable for micro aerial vehicles because it does not need any extra equipment for the VTOL maneuver. The developed tail-sitter aerial robot is equipped with four actuators for controlling ailerons, an elevator, a rudder and a propeller. A micro computer, various sensors and a battery are mounted on the aerial robot for autonomous flight without any support from a ground system. A transition flight strategy is constructed so that the transition finishes in the shortest time restricting an altitude change. In order to achieve the transition strategy, the reference trajectory of the pitch angle is computed offline by using an optimization technique. In the transition flight control system, a PID feedback controller is applied to attitude control, while a feedforward controller is applied to altitude control. The gain scheduling is applied to the control of the rudder and aileron. The experimental results on the transition between level flight and hovering, takeoff, and landing are presented. [ABSTRACT FROM AUTHOR]

One of the aims of air data systems is the determination of flight parameters angles of attack and angle of sideslip from measurements of local pressures and of local flow angles on wings or fuselage using a proper set of sensors. The active and integrated use of flight parameters in a full-authority flight control system imposes requirements for accurate and reliable air data, which are critical to maintain control. In this paper, a methodology based on the data fusion using Extended Kalman Filter technique is applied to dynamic maneuvers with rapid variations in the aircraft motion to calibrate angle of attack and angle of sideslip. The main goal of the investigations reported in this paper is to obtain online accurate flow angles from the measured vane deflection and difference pressures from probes sensitive to flow angles even in the adverse effect of wind or turbulence. The investigations are initially made on simulated flight data with wind and turbulence effects and it is showed that both alpha and beta estimates are accurate. The same procedure is then extended to flight test data of a high performance fighter aircraft. It has been shown using these results that sensor data fusion approach proposed in this paper is of great value in online implementation. [ABSTRACT FROM AUTHOR]

The operations of Cassini optical remote sensing instruments require a high level of spacecraft-pointing stability to minimize image distortion during an exposure window. This paper summarizes the flight performance of the Cassini spacecraft's pointing stability with respect to mission requirements. Sources of spacecraft jitter, the Cassini spacecraft control modes, and pointing-stability metrics are discussed to provide a context for the results. In designing the Cassini attitude-control system, a pointing-stability performance metric that considered the frequency contents of the disturbance sources was employed. Cassini pointing-stability results using the root-mean-square stability metric are provided for both spacecraft control modes, using the reaction-wheel assembly or the reaction control system composed of eight thrusters. The pointing-stability results are then related to characteristics of the spacecraft and operations. For thruster-based control, the pointing-stability results are analyzed with respect to the per-axis dead band. Results from the scientific instruments onboard the Cassini spacecraft confirm that the pointing-stability results in either control mode have achieved high accuracy pointing capabilities critical to the success of the mission and have resulted in data to improve our understanding of Saturn. [ABSTRACT FROM AUTHOR]

The research team from Control and Avionics Department of Rzeszow University of Technology (RUT) has been working on control systems for many types of flying objects for years. Experiences the team has had during their activity have helped create the control algorithms for a medium-size flying target (MSFT). Researchers from RUT, together with the small aviation company EUROTECH, have been working on a flying target for artillery. This paper gives a generic view of the system, including airborne and on-ground parts. But this paper mainly presents the control system that is mounted on the MSFT. The paper describes the generic conception of the control system of the flying target, including control laws used in the control system of the MSFT. Results of simulations and real flight data are also presented. [ABSTRACT FROM AUTHOR]

The main factor in design and operation of aircraft is safety of an airplane. The “safety culture” developed in aeronautics results in detailed regulations and certification procedures in all phases of aircraft design and operation. But despite that, aircraft safety depends on several unpredictable factors, such as the hostile actions both inside and outside of the aircraft. When failures occur during the flight, the most important actions are aimed at maintaining the aircraft controllability. The aircraft control system should be fault tolerant and ensure aircraft controllability in the event of the failure of a part of the flight control system. In this paper the influence of control surface failures on autopilot operation has been investigated. The autopilot is designed for business jet airplanes and fulfills the main functions of the real autopilot system in longitudinal and lateral directions. The autopilot structure allows implementation of various methods of reconfiguration for aircraft protection. [ABSTRACT FROM AUTHOR]

Reusable launch vehicles are a promising business for the future because of their flexibility, reliability, low cost, and good operability. There are two takeoff styles: the vertical takeoff and the horizontal takeoff. Compared to the horizontal takeoff vehicle, the vertical takeoff reusable launch vehicle has advantages, such as a shorter down-range landing, a quicker recovery system (wherein takeoff and landing happen in approximately the same location), and a lighter weight. A vertical profile is used for vertical takeoff and vertical landing (VTVL) vehicles to achieve a recovery at the launch site. However, the first stage of the vertical takeoff reusable launch vehicle (RLV) typically can provide a very small or even zero velocity to its second or upper stage, if the upper stage is released at the peak altitude. Therefore, primarily, this type of launch vehicle is used to achieve hundreds of seconds in a microgravity environment. The upper stage payload delivery capabilities of a vertical takeoff RLV and its potential applications are described from a trajectory point of view. A modified optimal control methodology and an intuitive method of the trajectory control, called energy for altitude and time, are used to determine the maximum throw distance, maximum flight time, and orbital insertion capabilities for certain payloads, separately. The results from this investigation show the possibilities of expanding the applications for the VTVL suborbital RLV. [ABSTRACT FROM AUTHOR]

Radar deception through phantom track generation using multiple electronic combat air vehicles is addressed, which serves as a motivating example for cooperative control of autonomous multiagent systems. A general framework to derive sufficient conditions for the existence of feasible solutions for an affine nonlinear control system comprising of a team of nonholonomic mobile agents having to satisfy actuator and interagent constraints is presented. Based on this feasibility analysis, an algorithm capable of generating trajectories online and in real time, for the phantom track generation problem, is developed. A rigorous treatment of the phantom track generation problem, which includes results on its accessibility, feasibility, local asymptotic straightening of trajectories, and a limited result on system controllability, is given. The basic approach to the algorithm based on the results developed here is presented along with simulation results, validating the proposed approach. [ABSTRACT FROM AUTHOR]

Abstract: The technique of inverse simulation is finding application in many and varied fields. As the name implies this technique is used to calculate the control action required to achieve a specified system response. The field of aircraft flight dynamics is particularly suited to this form of simulation as the question of what control actions must the pilot (or automatic flight control system) take for the aircraft to fly along a particular trajectory (a landing approach, for example) is often asked. This paper looks specifically at the application of inverse simulation in flight dynamics. The aim is not only to give an overview of the various techniques and applications but also to provide guidance to potential users of the technique on several of the physical and numerical features often observed in the results. An extensive review of the methodologies used within the family of inverse simulations is presented followed by a formal treatment of the theoretical development of inverse simulation as an established technique. A case study involving the inverse simulation of a helicopter flying a slalom manoeuvre is presented to demonstrate the application of inverse simulation in a flight dynamics analysis. An important feature of the use of inverse simulation is that it is necessary to define the output response required—in the case of flight dynamics the required flight path has to be modelled. Some of the methods used are documented, and their validity discussed. The paper also gives an insight into the types of problem which can be addressed by inverse simulation by detailing some of the many applications to which it has been put in the past. These include studies of rotorcraft handling qualities, performance and design, and pilot modelling as well as model validation. An important element of this paper is the formal, theoretical analysis of some of the numerical and physical features exhibited by inverse simulation which should aid potential users to interpret their results. The work presented in this paper shows a clear evolution of inverse simulation from its initial days when the mathematical models used were relatively simple into a mature analytical technique able to incorporate state of the art mathematical models and be applied to real flight dynamics problems. [Copyright &y& Elsevier]

The dynamic growth of general aviation as a mean of transport over medium distances means that people having no extraordinary qualifications or extraordinary physical or mental abilities more often pilot such types of airplanes. This phenomenon creates the necessity of giving planes flying qualities that allow them to be safely piloted by ordinary people. One way of solving this problem is equipping airplanes with fly-by-wire control systems that modify their handling qualities. Then the computer included into such control systems modifies the actions taken by the pilot, making the airplane both easier and more comfortable to control. This paper presents sample software tools — control algorithms that allowing an airplane's handling qualities to be improved. They are prepared by the authors and tested on board an experimental plane. That plane was equipped with a prototypical fly-by-wire control system, which can modify a plane's responses to a pilot's actions. Selected results of flying tests of this control system that modifies handling qualities are presented in this paper. Those results were a starting point for investigations to rate and compare the handling qualities of a plane equipped with a control system working according to the algorithms tested. [ABSTRACT FROM AUTHOR]

The objective of this study is to demonstrate the concept of active trailing-edge flaps as primary flight control and vibration reduction devices for a typical full-scale helicopter. A comprehensive rotorcraft analysis based on UMARC was developed to analyze the swashplateless rotor. A parametric study of various key design variables involved in the trailing-edge flap design was carried out. An optimal design of a trailing-edge flap system that provides effective control authority within the complete range of advance ratios as well as minimum actuation requirements was achieved. Trailing-edge flaps demonstrated the capability of performing both primary flight control and active vibration control functions. At a high forward speed (advance ratio of 0.32), the 4/rev vertical force and roll and pitch moments at hub ate successfully eliminated (by 90%), and the 4/rev in-plane hub forces are reduced by more than 40%. The half peak-to-peak value of the trailing-edge flap deflection for primary flight control is 7.1 deg, and an additional 4.7 deg is required for active vibration control. [ABSTRACT FROM AUTHOR]

Abstract: The handling qualities of an aircraft will be improved if the Direct Lift Control (DLC) system is applied. In this paper, an attempt has been made to evaluate the influence of DLC-type system parameters on the aircraft''s maneuverability and to determine the desired values of these parameters for the purpose of obtaining required values of the handling maneuverability criteria. Published papers which deal with direct lift control do not list requirements for evaluating handling qualities and maneuverability of aircraft equipped with DLC system. In this paper, three new criteria permitting the evaluation of results of employing DLC have been defined. Analysis of influence of DLC system parameters on selected known handling qualities criteria (for example CAP, ), as well as new DLC efficiency coefficients, have been illustrated with a numeric example of A4D “Skyhawk” fighter aircraft and PZL M-18 “Dromader” agricultural airplane control system modification. [Copyright &y& Elsevier]

The results of calculation of the required lateral range are presented for the orbital reentry of a spacecraft having a preset inclination and preset ascending node longitude to land at a preset point on the Earth's surface. The suboptimum laws of roll angle variation in velocity are determined, which allows one to reach the maximum available lateral range for a given value of constant lift-to-drag ratio taking into account constraints imposed on the maximum equilibrium temperature. [ABSTRACT FROM AUTHOR]

A genetic algorithm (GA), a well-known numerical method, is widely applied in different areas of optimal studies. It is found that if the solution-search space is wide or if the selected fitness function is highly nonlinear, the GA’s solutions can strongly depend on the set parameters, which include population size, crossover rate, mutation rate, and the remaining size of the parent in the GA. This paper combines the Taguchi experimental method, which serves as a rough search tool, with the GA, which serves as a fine search tool, to find the best combination of the GA parameters for different flight-control problems. The purpose of such a combination is to make control more robust and closer to the optimal solution. To demonstrate this new idea, the writers consider its application to different flight-control problems for the F-16 fighter by using autostabilization, linear quadratic regulator (LQR) and H∞ design. The simulation results not only achieve the expected optimal design for flight-control problems but also justify the reliability and feasibility of the combination of the GA and the Taguchi method. [ABSTRACT FROM AUTHOR]

With the wider use of composite materials in aviation, the observation of their quality during production and exploitation is becoming more topical. We are of the opinion that acoustic technologies of all-in-one control give us promising possibilities to watch and research the characteristics and parameters of composite materials. The acceptable way to form acoustic scenery for composite material research is discussed in this paper. [ABSTRACT FROM AUTHOR]

A long-term goal for general aviation aircraft is to reduce or eliminate the use of fluid power systems such as hydraulics from the aircraft. Power-By-Wire (PBW) technology seems to be the next major step in the development of aircraft control. In this solution, control power comes directly from the aircraft electrical system to the Electro-Mechanical Actuator (EMA), which includes the electric motor, controller and gearbox. EMAs have the potential to be more efficient, less complicated, less expensive, and more faults tolerant than actuators based on hydraulic systems. The construction of a single EMA and set of cooperating electro-mechanical servos actuating airplane control surfaces is presented in this work. The mechanical unit, microcontroller of the EMA, and general information on control algorithms are discussed in this work. Testing methods and laboratory results are also described. Then the in-flight testing results of the complete set of servos installed as a part of a SPS-1 system on board an airplane are presented. SPS-1 is an experimental Fly-By-Wire (FBW) control system for general aviation aircraft designed as a project financed by the Polish State Committee for Scientific Research (2004-2005). [ABSTRACT FROM AUTHOR]

A rational and robust scheme for obtaining recovery controls for nonlinear flight conditions, such as spins, is presented. In a spin, the loss of control due to the large angular rates and high angle of attack that the airplane experiences could lead to disastrous situations in general aviation. In this study, to arrest rotation and at the same time recover from a spin, the directions and magnitudes of linear and angular momentum vectors are effected to restore their prespin conditions. The problem of computation of the required controls is formulated as a nonlinear programming problem. Simulated time histories are presented and compared to the actual flight-test data for a light, single-engine general aviation aircraft. The proposed method produced effective control time histories for recovery from both a steep and a flat spin, demonstrating the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

The main goal of the presented project is to improve safety and Handling Qualities of general aviation aircraft so that airplane becomes pilot-friendly, “almost unmanned” aircraft. In this paper, a proposal of employing an intuitive, human-centered, simplified software-based flight control system in general aviation aircraft has been presented. Airplanes equipped with such a flight control system belong to a new class of general aviation aircraft with improved safety and efficiency handling properties – Facilitated Airplane (FA) or Simple Flying Airplane (SFA).The basic idea of the project is to employ an indirect (Fly-by-Wire) software-based flight control system characterized by high degree of automatization, leading to an almost “unmanned” general aviation aircraft. “Unmanned” does not mean eliminating humans from the control process but changing their role in the system. User-friendly control system should shape handling qualities of an aircraft in such a way that control becomes easy and safe. Pilot retains the crucial role of decision-maker, and control system takes appropriate steps to fulfill his requirements, or suggests optimal methods of implementing his decisions. Such a system may be considered to be pilot''s electronic assistant as it integrates simplified handling flight controls and autopilot functions, and reduces the complexity of interactions between aircraft attitudes, power settings, and rate of motion, and in conclusion limits the possibility of loss of control. [Copyright &y& Elsevier]

Weight and longitudinal center-of-gravity position of an aircraft are valuable information for flight monitoring, automatic flight control, and fault detection and identification algorithms. In trimmed symmetric flight (as cruise, climb, or descent) the aircraft weight is counteracted mainly by the aerodynamic lift, whereas the associated couple is counterbalanced by a moment generated by an appropriate elevator deflection. Because, for given flight conditions, the aerodynamic lift and pitching moment are functions of the angle of attack and elevator deflection only, the last two variables carry the information about the aircraft weight and its longitudinal center-of-gravity position. It is demonstrated that this information can be effectively recovered in flight using nonparametric artificial neural networks (NNs), pretrained on flight-test data. To enhance the accuracy and speed up the training process, basic flight mechanics relations are incorporated into the NN. It is also demonstrated that the NN-based lift and pitching moment functions can be used a posteriori to estimate the aircraft longitudinal neutral point. [ABSTRACT FROM AUTHOR]

A perspective on the practice, issues, and potential of aeroelasticity is presented. The issues of cycle time reduction and improvements in the fidelity of aeroelastic analysis need to be emphasized for aeroelasticity to support adequately the airplane configuration development and configuration decisions. The introduction of fly-by-wire control systems has increased the complexity as well as the fidelity requirements for the aeroelastic analysis. The business cost of inaccuracies in loads and dynamics predictions can be seriously high. Therefore, innovative approaches should be encouraged to address these issues. Aeroelasticity has an opportunity to contribute to airplane design by evolving to become a more integrating discipline. Although many of the methods and processes in different subdisciplines are in place already, others need to be developed further for improved usability, efficiency, fidelity, and integration. The most challenging problems in realizing the full potential of aeroelasticity are not just technical but are also organizational in nature. The organizational issues are related to management of multidisciplinary teams in a lean engineering environment. Thus, to realize the multidisciplinary integrating potential of aeroelasticity and its contributions to the configuration decisions, technical and management foresight, leadership, and vision are required. [ABSTRACT FROM AUTHOR]

This paper reviews selected UAV applications and aircraft configurations as functions of these applications. Very unusual configurations are often observed and this paper tries to explain that the final aircraft layout is a trade-off between aerodynamic efficiency, the flight control system (usually very expensive), stealth (in the military sector), payload, reliability, and safety. This paper also accentuates some universal aspects and features of all aerospace designs, namely safety, reliability, cost, and economical competitiveness. These issues can be found on the priority lists both defined by NASA (the so-called "Blueprints for Aeronautics") and by the European Commission under the umbrella of the VIth Framework Programme of the European Union. The paper often refers to the UAVNET network and both to its achievements and results presented within regular seminars organised by UAVNET. [ABSTRACT FROM AUTHOR]

Gyroscope devices are primary units for navigation and control systems in aviation and space engineering. The main property of the gyroscope is maintaining the axis of a spinning rotor, based on the principles of the angular momentum of the spinning rotor. However, the nature of the gyroscope’s acting forces and motions is more complex. The torque applied to the gyroscope generates the internal resistance and precession torques based on acting simultaneously and interdependently, namely, centrifugal, common inertial and Coriolis forces generated by the mass elements of the spinning rotor as well as changes in angular momentum. This system of internal torques based on new fundamental principles of the gyroscope theory that enabled deriving the mathematical model for the motions of a gyroscope suspended from the flexible cord, which was a most unsolvable problem. The test results of the gyroscope motions well validated the new analytical approach. [ABSTRACT FROM PUBLISHER]

The article offers information on designing of test rigs by the authors for the project on development of mini helicopter. It states that the three-axis rig is designed to have three motions which can be independently locked or set free. It mentions that this experimental design was set up to test control algorithms developed for flight control of the helicopter. It reports that in the first step pitch control of the vehicle was undertaken in which yaw and roll motions were locked in the rig.