A Linear Domain System Identification for Small Unmanned Aerial Rotorcraft Based on Adaptive Genetic Algorithm

<正> This paper proposes a new adaptive linear domain system identification method for small unmanned aerial rotorcraft.Byusing the flash memory integrated into the micro guide navigation control module, system records the data sequences of flighttests as inputs (control signals for servos) and outputs (aircraft's attitude and velocity information).After data preprocessing, thesystem constructs the horizontal and vertical dynamic model for the small unmanned aerial rotorcraft using adaptive geneticalgorithm.The identified model is verified by a series of simulations and tests.Comparison between flight data and the one-stepprediction data obtained from the identification model shows that the dynamic model has a good estimation for real unmannedaerial rotorcraft system.Based on the proposed dynamic model, the small unmanned aerial rotorcraft can perform hovering,turning, and straight flight tasks in real flight tests.     

Collision avoidance in commercial aircraft Free Flight via neural networks and non-linear programming

In recent years there has been a great effort to convert the existing Air Traffic Control system into a novel system known as Free Flight. Free Flight is based on the concept that increasing international airspace capacity will grant more freedom to individual pilots during the enroute flight phase, thereby giving them the opportunity to alter flight paths in real time. Under the current system, pilots must request, then receive permission from air traffic controllers to alter flight paths. Understandably the new system allows pilots to gain the upper hand in air traffic. At the same time, however, this freedom increase pilot responsibility. Pilots face a new challenge in avoiding the traffic shares congested air space. In order to ensure safety, an accurate system, able to predict and prevent conflict among aircraft is essential. There are certain flight maneuvers that exist in order to prevent flight disturbances or collision and these are graded in the following categories: vertical, lateral and airspeed. This work focuses on airspeed maneuvers and tries to introduce a new idea for the control of Free Flight, in three dimensions, using neural networks trained with examples prepared through non-linear programming.     

The Model Identification for Small Unmanned Aerial Rotorcraft Based on Adaptive Ant Colony Algorithm

This paper proposes a model identification method to get high performance dynamic model of a small unmanned aerial rotorcraft.With the analysis of flight characteristics,a linear dynamic model is constructed by the small perturbation theory.Using the micro guidance navigation and control module,the system can record the control signals of servos,the state information of attitude and velocity information in sequence.After the data preprocessing,an adaptive ant colony algorithm is proposed to get optimal parameters of the dynamic model.With the adaptive adjustment of the pheromone in the selection process,the proposed model identification method can escape from local minima traps and get the optimal solution quickly.Performance analysis and experiments are conducted to validate the effectiveness of the identified dynamic model.Compared with real flight data,the identified model generated by the proposed method has a better performance than the model generated by the adaptive genetic algorithm.Based on the identified dynamic model,the small unmanned aerial rotorcraft can generate suitable control parameters to realize stable hovering,turning,and straight flight.     

Model Identification of a Micro Air Vehicle

This paper is focused on the model identification of a Micro Air Vehicle （MAV） in straight steady flight condition. The identification is based on input-output data collected from flight tests using both frequency and time dorrtain techniques. The vehicle is an in-house 40 cm wingspan airplane. Because of the complex coupled, multivariable and nonlinear dynamics of the aircraft, linear SISO structures for both the lateral and longitudinal models around a reference state were derived. The aim of the identification is to provide models that can be used in future development of control techniques for the MAV.     

Aeromedical Aspects of Factor Risk Management for Flight Safety

This article considers the theoretical basics of the flight safety risk management concept that are related to arranging and conducting aeromedical support activities for civil aviation. The characteristic of procedures of discovering flight safety risk factors and hazards is presented. The concept of medical risk is defined. The process of managing risk factors related to changes in the health state of aviation staff is considered. The practical significance of the flight safety risk management concept for the health assessment of aviation and airline traffic control staff is shown.     

Visual control of prey-capture flight in dragonflies

Interacting with a moving object poses a computational problem for an animal's nervous system. This problem has been elegantly solved by the dragonfly, a formidable visual predator on flying insects. The dragonfly computes an interception flight trajectory and steers to maintain it during its prey-pursuit flight. This review summarizes current knowledge about pursuit behavior and neurons thought to control interception in the dragonfly. When understood, this system has the potential for explaining how a small group of neurons can control complex interactions with moving objects.     

Flight mechanics of a tailless articulated wing aircraft

This paper investigates the flight mechanics of a micro aerial vehicle without a vertical tail in an effort to reverse-engineer the agility of avian flight. The key to stability and control of such a tailless aircraft lies in the ability to control the incidence angles and dihedral angles of both wings independently. The dihedral angles can be varied symmetrically on both wings to control aircraft speed independently of the angle of attack and flight path angle, while asymmetric dihedral can be used to control yaw in the absence of a vertical stabilizer. It is shown that wing dihedral angles alone can effectively regulate sideslip during rapid turns and generate a wide range of equilibrium turn rates while maintaining a constant flight speed and regulating sideslip. Numerical continuation and bifurcation analysis are used to compute trim states and assess their stability. This paper lays the foundation for design and stability analysis of a flapping wing aircraft that can switch rapidly from flapping to gliding flight for agile manoeuvring in a constrained environment.     

Lessons from Immune 1-3: what did we learn and what do we need to do in the future?

Sprague-Dawley rats were subjected to three 8-to-10 day space flights on the Space Shuttle. Housed in NASA's Animal Enclosure Modules, rats were flown to test the hypotheses that therapy with pegylated interleukin-2 or insulin-like growth factor-1 would ameliorate some of the effects of space flight on the immune system. As part of these experiments, we measured body and organ weights, blood cell differentials, plasma corticosterone, macrophage colony forming units, lymphocyte mitogenic, super-antigenic and interferon-gamma responses, bone marrow cell and peritoneal macrophage cytokine secretion and bone strength and mass. This paper compares some of the immunophysiological parameters of the control animals used in the Immune1-3 flight series and presents data from an animal infection model for use during space flight.     

Human error and the problem of causality in analysis of accidents

Present technology is characterized by complexity, rapid change and growing size of technical systems. This has caused increasing concern with the human involvement in system safety. Analyses of the major accidents during recent decades have concluded that human errors on part of operators, designers or managers have played a major role. There are, however, several basic problems in analysis of accidents and identification of human error. This paper addresses the nature of causal explanations and the ambiguity of the rules applied for identification of the events to include in analysis and for termination of the search for 'causes'. In addition, the concept of human error is analysed and its intimate relation with human adaptation and learning is discussed. It is concluded that identification of errors as a separate class of behaviour is becoming increasingly difficult in modern work environments. The influence of this change on the control of safety of large-scale industrial systems is discussed.     

The Function of Dipteran Flight Muscle

The flight muscles of flies are separated into two physiologically, anatomically, and functionally distinct classes: power muscles and control muscles. The large indirect power muscles sustain the high level of mechanical energy required to flap the wings up and down during flight. The contractions in the asynchronous power muscles are initiated by stretch, and their slow presynaptic motor drive serves only to maintain a tonic level of cytosolic calcium. Although providing the mechanical energy for flight, the power muscles are not directly attached to the wings. Instead, their mechanical energy is transmitted to the base of the wings through the complex linkage system of the wing hinge. In contrast, the small control muscles insert directly onto the skeletal elements at the base of the wing. Through their mechanical effects on the hinge, the control muscles act collectively as a transmission system that determines how the mechanical energy produced by the power muscles is transformed into wing motion. The control muscles are activated by motor spikes in the conventional one-for-one fashion. Thus, although the control muscles can generate little mechanical power, they provide the means by which the nervous system can rapidly alter wing kinematics during sophisticated aerial maneuvers.     

Diacylglycerol-transporting lipoproteins and flight in Locusta

Evidence from chromatographic and heparin precipitation studies shows that the ‘heparin-soluble’ lipoprotein, A⁺, forms in the haemolymph during flight. In locusts flown continuously for 60 min, lipoprotein A⁺ occurs in the haemolymph at low concentrations but accumulates during a short rest period following flight. After injections of tissue extracts containing adipokinetic hormone (AKH), A⁺ accumulates in the haemolymph but disappears more rapidly in flying locusts than in resting locusts. This difference in the rate of disappearance of diacylglycerol from the lipoprotein A⁺ can be used to estimate its rate of utilization during sustained flight (approx. 100μg. min^?1 from 45–90 min of flight). It is suggested that lipoprotein A⁺ is the major carrier of diacylglycerol from the fat body to the flight muscles during prolonged flight. The steady state concentrations of total diacylglycerol and ‘heparin-soluble’ diacylglycerol during continuous flight are unaffected when tissue extracts containing AKH are injected before flight. This suggests that there is a close homeostatic control over the steady state concentration of haemolymph lipid during flight.     

Recording of blood pressure,heart rate and aortic nerve activity during parabolic flight in the rat via radio-telemetry

Exposure to microgravity induces cardiovascular deconditioning characterized by orthostatic hypotension when astronauts return to the earth. In order to understand the mechanism of cardiovascular deconditioning, it is necessary to clarify the changes in hemodynamics and the cardiovascular regulation system over the period of space flight. The telemetry system applied to freely moving animals will be a useful and appropriate technique for this kind of long term study of the cardiovascular system in the conscious animal during space flight. The purpose of the present study is twofold: firstly, to observe the detailed changes of arterial pressure and heart rate (HR) during microgravity elicited by the parabolic flight in order to study the acute effect of microgravity exposure on the cardiovascular system; and secondly, to test the feasibility of the telemetry system for recording blood pressure, HR and autonomic nervous activities continuously during space flight.     

Development of a whole blood staining device for use during space shuttle flights.

BACKGROUND: Exposure to microgravity during space flight results in profound physiologic changes. Numerous studies have shown changes in circulating populations of peripheral blood immune cells immediately after space flight. It is currently unknown if these changes result from exposure to microgravity or are caused by the stress of reentry and readaptation to gravity. METHODS: We have developed the whole blood staining device (WBSD) as a system for the staining of whole blood collected during space flight for subsequent flow cytometric analysis. This device contains all liquids to address safety issues concerned with space flight and also moves the cells through the staining, lyse/fixation, and dilution steps. RESULTS: Data from flow cytometric analysis of samples stained in the WBSD was found to be comparable to data from samples stained by the conventional methods. Cells stained with the WBSD remain stable in the device for up to 14 days. The necessary manipulations required to use the device were tested on the KC-135 aircraft during the reduced gravity segment of parabolic flight. CONCLUSIONS: With the WBSD immunophenotype analysis can be performed at various time points for the duration of an entire Shuttle flight. In addition, this device has significant terrestrial applications for rapid and easy immunofluorescence labeling of whole blood in remote and isolated locations where immediate access to specialized equipment and skilled laboratory personnel may not be available. The WBSD provides a simple mechanism to design specific immunophenotyping tests for use by nontechnical personnel at bedside or in field locations. Cytometry 37:74-80, 1999. Published 1999 Wiley-Liss, Inc.     

Independently Controlled Wing Stroke Patterns in the Fruit Fly Drosophila melanogaster

Flies achieve supreme flight maneuverability through a small set of miniscule steering muscles attached to the wing base. The fast flight maneuvers arise from precisely timed activation of the steering muscles and the resulting subtle modulation of the wing stroke. In addition, slower modulation of wing kinematics arises from changes in the activity of indirect flight muscles in the thorax. We investigated if these modulations can be described as a superposition of a limited number of elementary deformations of the wing stroke that are under independent physiological control. Using a high-speed computer vision system, we recorded the wing motion of tethered flying fruit flies for up to 12 000 consecutive wing strokes at a sampling rate of 6250 Hz. We then decomposed the joint motion pattern of both wings into components that had the minimal mutual information (a measure of statistical dependence). In 100 flight segments measured from 10 individual flies, we identified 7 distinct types of frequently occurring least-dependent components, each defining a kinematic pattern (a specific deformation of the wing stroke and the sequence of its activation from cycle to cycle). Two of these stroke deformations can be associated with the control of yaw torque and total flight force, respectively. A third deformation involves a change in the downstroke-to-upstroke duration ratio, which is expected to alter the pitch torque. A fourth kinematic pattern consists in the alteration of stroke amplitude with a period of 2 wingbeat cycles, extending for dozens of cycles. Our analysis indicates that these four elementary kinematic patterns can be activated mutually independently, and occur both in isolation and in linear superposition. The results strengthen the available evidence for independent control of yaw torque, pitch torque, and total flight force. Our computational method facilitates systematic identification of novel patterns in large kinematic datasets.     

Antioxidant metabolism in Xenopus laevis embryos is affected by stratospheric balloon flight

To test the effects of low levels of radiation from space on living organisms, we flew Xenopus laevis embryos at different stages of development on a stratospheric balloon (BI.R.BA mission). After recovery, different parameters were analyzed to assess the effects of flight, with particular regard to oxidative stress damage. Because of failed temperature control during flight, the flight shielded embryos (FC) could not be used for biochemical or morphological comparisons. In contrast, the incubation conditions (i.e. temperature, containers, volumes) for the flight embryos (F) were parallel to those for the ground controls. Mortality data show that younger embryos (16 h) flown on the balloon (F) are more sensitive to radiation exposure than older ones (40 h and 6 days). Exposure during flight lowered the antioxidant potential in all embryos, particularly older ones. These preliminary data demonstrate that flight on a stratospheric balloon might affect antioxidant metabolism, though it is not yet possible to correlate these results with low radiation exposure during flight.     

Increased juvenile hormone levels after long-duration flight in the grasshopper, Melanoplus sanguinipes

Although, in many insects, migration imposes a cost in terms of timing or amount of reproduction, in the migratory grasshopper Melanoplus sanguinipes performance of long-duration flight to voluntary cessation or exhaustion accelerates the onset of first reproduction and enhances reproductive success over the entire lifetime of the insect. Since juvenile hormone (JH) is involved in the control of reproduction in most species, we examined JH titer after long flight using a chiral selective radioimmunoassay. JH levels increased on days 5 and 8 in animals flown to exhaustion on day 4 but not in 1-h or non-flier controls. No difference was seen in the diel pattern of JH titer, but hemolymph samples were taken between 5 and 7 h after lights on. Treatment of grasshoppers with JH-III mimicked the effect of long-duration flight in the induction of early reproduction. The increased JH titer induced by performance of long-duration flight is thus at least one component of flight-enhanced reproduction. To test the possibility that post-flight JH titer increases are caused by adipokinetic hormone (AKH) released during long flights, a series of injections of physiological doses of Lom-AKH I were given to unflown animals to simulate AKH release during long flight. This treatment had no effect on JH titers. Thus, although AKH is released during flight and controls lipid mobilization, it is not the factor responsible for increased JH titers after long-duration flight.     

Modification of landing conditions at contact via flight

Weight-bearing tasks performed by humans consist of a series of phases with multiple objectives. Analysis of the relationship between control and dynamics during successive phases of the tasks is essential for improving performance without sustaining injury. Experimental evidence regarding foot landings suggests that the distribution of momentum among segments at contact influences stability during interaction with the landing surface. In this study, we hypothesized that modification of control in one subsystem, in our case shoulder torque, during the flight phase of an aerial task would enable the performer to maintain behavior of other subsystems (e.g.lower extremity kinematics) and initiate contact with momentum conditions consistent with successful task performance. To test this hypothesis, an experimentally validated multilink dynamic model that incorporated modifications in shoulder torque was used to simulate the flight phase dynamics of overrotated landings. The simulation results indicate that modification in shoulder torque during the flight phase enables gymnasts to maintain lower extremity kinematics and initiate contact with trunk angular velocities consistent with those observed during successful landings. These results suggest that modifications in the control logic of one subsystem may be sufficient for achieving both global and local task objectives of landing.     

Congestion Transition in Air Traffic Networks

Air Transportation represents a very interesting example of a complex techno-social system whose importance has considerably grown in time and whose management requires a careful understanding of the subtle interplay between technological infrastructure and human behavior. Despite the competition with other transportation systems, a growth of air traffic is still foreseen in Europe for the next years. The increase of traffic load could bring the current Air Traffic Network above its capacity limits so that safety standards and performances might not be guaranteed anymore. Lacking the possibility of a direct investigation of this scenario, we resort to computer simulations in order to quantify the disruptive potential of an increase in traffic load. To this end we model the Air Transportation system as a complex dynamical network of flights controlled by humans who have to solve potentially dangerous conflicts by redirecting aircraft trajectories. The model is driven and validated through historical data of flight schedules in a European national airspace. While correctly reproducing actual statistics of the Air Transportation system, e.g., the distribution of delays, the model allows for theoretical predictions. Upon an increase of the traffic load injected in the system, the model predicts a transition from a phase in which all conflicts can be successfully resolved, to a phase in which many conflicts cannot be resolved anymore. We highlight how the current flight density of the Air Transportation system is well below the transition, provided that controllers make use of a special re-routing procedure. While the congestion transition displays a universal scaling behavior, its threshold depends on the conflict solving strategy adopted. Finally, the generality of the modeling scheme introduced makes it a flexible general tool to simulate and control Air Transportation systems in realistic and synthetic scenarios.     

Development of a PWM Precision Spraying Controller for Unmanned Aerial Vehicles

This paper presents a new Pulse Width Modulation (PWM) controller for Unmanned Aerial Vehicle (UAV) precisionsprayer for agriculture using a TL494 fixed-frequency pulse width modulator together with a data acquisition board and developedsoftware. An UAV can be remotely controlled or flown autonomously by pre-programmed flight plans. The PWMcontroller was implemented through the guidance system on the UAV with control commands sent between the UAV helicopterand the ground control station via a wireless telemetry system. The PWM controller was tested and validated using LabVIEW8.2. Several analyses were performed in a laboratory to test different control signals. The results show that the PWM controllerhas promise as a higher precision technique for spray applications, which will improve efficiency of pesticide application,especially in crop production areas.     

铜绿假单胞菌的MALDI-TOF-MS检测方法的建立

目的 建立利用基质辅助激光解吸电离飞行时间质谱仪( MALDI-TOF-MS)对铜绿假单胞菌的快速检测方法.方法 通过MALDI-TOF-MS法对铜绿假单胞菌进行检测分析,并与生化鉴定方法相比较.结果 MALDI-TOF-MS对铜绿假单胞菌的检测后得到肽指纹图片及相关质谱数据,建立MALDI-TOF-MS对铜绿假单胞菌的快速检测方法.结论 MALDI-TOF-MS方法检测铜绿假单胞菌准确快速、操作简单等特点,可发展成为食品检验铜绿假单胞菌的重要(辅助)工具.