Verification of the method of finding a faulty sensor in reduced meters

The reliability of the method for determining a failed sensor in a redundant angular velocity meter (AVM) by means of its experimental verification is considered. The mutual non-orthogonal arrangement of six axes of sensor sensitivity has been optimized to reduce the instrumental errors of each sensitive element and ensure the equality of their contribution. Provides approximately the same sensitivity to the level of error in case of failure. One of the six experimentally obtained sensor signals contains an error that exceeds the specified permissible limit. The algorithm for searching for a sensor is checked, the error of which exceeds the specified one, and which, for this reason, is considered faulty.

Methodology for calculating the efficiency of the rudders of the tandem aircraft

As of recent rapid development in the field of UAVs, unusual aerodynamic practices can be used, for example, the tandem scheme. In early planning stages, it’s important to evaluate aerodynamic characteristics of the chosen scheme and to approximate its balancing losses, as it impacts the stability and controllability of the craft. The most effective way of aerodynamic characteristics analysis is done using wind tunnels. However, it requires considerable investments in both financial terms and time, when designing the model, conducting the experiment and processing the results. Because of that, it’s worthwhile to consider the simple CFD calculations (XFOIL). This paper calculates aerodynamic characteristics of a tandem-scheme based “A-8” aircraft using XFLR5 analysis tool with the results compared to a real wind tunnel experiment. The overall conclusion of the paper is a recommendation to consider XFLR5 for early planning stages for advanced balancing losses calculation approximation.

The development of the earth remote sensing from satellite

Remote sensing activities from satellite are important aspect togain information about earth surface, thus has important significance on military, economic and geology fields. After 1962, the term remote sensing became popular and typically refers to non-intrusive observation of the Earth using electromagnetic waves from a platform some distance away from the object of study. Remote sensing implies a measurement made by some indirect or “remote” means rather than by a contact sensor. Remote sensing platform of satellite serves the sensing by using sensors. There are two types of sensors active and passive sensors. This article reviews about the sensors which are used for remote sensing of earth from satellite. This article analyses the sensors for sensing purpose and for attitude control of the satellite.

Software complex for aircraft characteristics calculation

The article describes the method of calculating the aerodynamic loads of the aircraft, which can be programmed within the graphic user interface. The method uses statistical data of typical aerodynamic profiles flow in wind tunnels and mathematical expressions that describe the known laws of aerohydromechanics. The graphic user interface is tested by a model of the famous Ukrainian aircraft A32 that manufactured by Aeropract company. A surface model of the aircraft for modeling consists of the theoretical surface for the wing and the fuselage. A comparison of the formula’s calculation in the graphical interface and finite element calculations is given. The software interface is built in C #.

Determination of the aerodynamic characteristics of the tiltrotor with the wingtip-mounted coaxial rotors

The article describes the study of rotor-to-wing aerodynamic interaction for the wingtip-mounted coaxial rotors configuration of the tiltrotor aircraft. The influence of the rotor slipstreams on lift-to-drag ratio characteristic was determined. Obtained results were compared with similar characteristics of the equivalent in thrust conventional single rotor slipstreams impact. Using the computational aerodynamics methods (panel-vortex method) the flow around the tiltrotor model with the wingtip-mounted single and coaxial rotors has been simulated. A study of the basic model configuration with conventional single rotors, based on the technical characteristics of the AgustaWestland AW609 tiltrotor, was conducted. Further researches were conducted for a modified model where single rotors were replaced with equivalent in thrust coaxial rotors. The influence of the rotor slipstreams on the aerodynamic characteristics of the model for both directions of rotors rotation in coaxial combination is considered. Also, the dependence of the maximum lift-to-drag characteristic due to the coaxial rotor diameters change has been determined. The results show that the coaxial rotor slipstreams-to-wing aerodynamic interaction effect is the similar to the effect of conventional single rotor, but less intensive. Comparison of the results showed that a tiltrotor equipped with wingtip-mounted single rotors has approximately 20% greater maximum lift-to-drag characteristic than one equipped with coaxial rotors with the same thrust. However, the use of coaxial rotors allows getting higher maximum speed, when conventional single rotors lose the efficiency significantly. Therefore, it is advisable to conduct further research for the possibility of using coaxial rotors for tiltrotor aircrafts. The research results are presented in graphical form. The obtained data provides a basis for further studies of the described problem, and also will be useful for new tiltrotor design works.

Determination of meridian position by a two-step ground gyrocompass in eesthetical rotor positioning

Contradiction between accuracy and time of definition of a plane of a geographical meridian has significantly weakened with appearance of automatic gyrocompasses and algorithmic methods of processing of the information from them. These methods allow us to expand the range of possible modes of gyrocompasses, including non-traditional. The article considers an automatic two-stage ground gyro compass operating in the mode of natural stopping of the rotor after its pulse acceleration by non-electrical means (squib , compressed air, etc.). The specified mode is attractive because it allows to identify uncontrolled harmful moment around the axis of suspension in one start and significantly reduce the measurement time. In order to further improve the device, it is proposed to abandon the measurement of the current value of the kinetic moment, and to identify the decay coefficient of the exponential function by observing the azimuthal motion of the sensitive element of the device. Moreover, the paper shows that it is possible not to measure the initial value of the kinetic momentum, replacing the measurement with identification of this parameter by observing the same azimuthal motion of the sensitive element. In this case there is no need to have on the sensitive element any nodes associated with the transmission of power and electrical signals, the sensitive element can be made as a purely mechanical element, carrying on itself a rotating rotor. For all considered variants of measurement (or identification) of parameters the machine simulation was carried out, which confirmed the performance of the proposed methodology.

Information system for creating a generalized model of complex technical objects

Creation of complex technical objects (CTO, such as science-intensive engineering objects, which are characterized by the number of elements and connections equal to 106 and more) – a process containing long subprocesses, complex objects, models, and based on available standards and information technology (IT). It is known from practice that CTO models are created with the help of information systems - components of CALS and PLM-solutions. This process have the following shortcomings: models at different stages of creation of CTO are not completely interconnected; CTO modeling takes place using different components of IT CALS and PLM-solutions, which creates constant difficulties in data conversion and leads to partial or complete loss of model data; there is no automated communication with other CTO models. A generalized model of complex technical objects is proposed, which based on using the theoretical-multiple approach allows to establish an information connection between the models of the process of creating complex technical objects. The information system of creation of the generalized model of difficult technical objects that allowed automating process of processing and construction of models is developed; to supplement the technology of parallel PLM design and components of information technologies CALS and PLM-solutions for the task of creating models of complex technical objects.

Mathematical models of the gyrostabilizer in different modes of its operation

The article considers the development of a mathematical model of the stabilization and rotation system in the modes of stabilization, targeting, auto-tracking of the target and electrical arrest. The output signals shall be signals proportional to the components of the angular velocities of the line of sight, the angles of pitch and dash of deviation around the axes of the gyrosystem and the angles of inconsistency of the line of sight relative to the optical axis of the homing head. The system of cardan suspension of the stabilization and rotation system is considered, where the actuators are located on the axes of rotation of the outer and inner frames of the cardan suspension. The homing head is mounted on the inner frame. The inner frame is a gyrostabilized platform. Depending on the mode of operation of the stabilization and rotation system: in the stabilization mode, the coordinate system that is stabilized is assumed to be stationary in inertial space; in the auto-tracking mode of the target, the coordinate system that is stabilized by Oxyz is returned according to the change of direction to the target; in the mode of electrical locking, the axes of the coordinate system which is stabilized by Oxyz coincide with the axes of Oxoyozo connected to the body of the main product. To obtain differential equations, the projections of the total vector of the kinetic moment of the inner and outer frames on the axis of the outer frame are taken and written according to the theorem on the change of the kinetic moment of the considered system relative to the axes of suspensions. The total moments of external forces applied to the outer and inner frames around their axes of rotation, which have the following components: moments of actuators, moments of viscous and dry friction, imbalance and other unaccounted for factors around the axes of the outer and inner frames . The moments of the forces of viscous and dry friction are presented in the classical form, taking into account the signs when changing the direction of movement. The mass of the inner frame with all devices mounted on it, and the mass of the entire movable system (outer and inner frames), as well as the radius vector characterizing the displacement of the center of mass, give a static imbalance of the movable system relative to the suspension axis of the i-th frame are components imbalance. The scientific novelty of the work is to obtain a mathematical model for a particular product, as well as the practical feasibility of their application. The result is a differential equation that fully describes this system of stabilization and rotation, takes into account the parameters of actuators, turbulent moments, as well as random effects and can be used depending on the tasks.

Influence of the rotor propulsor on the characteristics of the power unit integrated with wing

Fan wing concept increased the efficiency of using the kinetic energy of the movement of air that flows around the wing. It allow generate thrust and lifting forces. But this scheme also has drawbacks. The most important associated with the significant drag force. The large diameter of the cross-flow fan, in case of failure of the power plant, the aerodynamic quality will be approximately 1: 3. To improve parameters and increase the feasibility of using this scheme, we need to review the existing concepts and change the basic geometric parameters of the cross-flow fan and try to reduce the diameter. It is advisable to increase the speed of its rotation. This work performed calculation and compare lift force and thrust force generated by the system. Compare various positions of the blades, and airflow rate at the outlet of the engine by numerical simulation. Also studied the effect of the profile shape of the blades and their amounts on the performance. As a result, analysis of the interaction of all these parameters to determine the model with the best aerodynamic performance. Numerical modeling turned out to be very resource-intensive. So the main focus on a series of physical experiments with real models. The results show that this scheme has more benefits when compared with before use. So, the proposed idea has good prospects for development and application.

Classification and analysis of measuring transducers of intensity (induction) of alternating magnetic fields

The current state of technology is characterized by the mass use of electricity, the use of various electrical, electronic and radio devices. This causes expansion of magnetic measurements and the need to develop new highly sensitive measuring equipment for a wide range of frequencies. One of its main elements, that largely determines the accuracy, frequency and dynamic ranges, are the primary measuring sensors of strength (induction) of alternating magnetic fields. Many works have been devoted to the analysis and development of various sensors of strength (induction) of magnetic fields. At the same time, it can be noted the lack of a systematic approach to the measurement of alternating magnetic fields. The problem of the general classification of methods of measurement of alternating magnetic fields and, accordingly, primary measuring sensors of strength (induction) of alternating magnetic fields is not solved. In most cases, separate issues of measuring alternating magnetic fields and certain types of sensors are considered. That does not allow obtaining a holistic picture in this area and make the right choice of direction for solving assigned tasks. The comprehensive analysis of methods of measuring alternating magnetic fields was carried out in this work. Based on it, the classification of primary measuring sensors of strength (induction) of alternating magnetic fields, on the physical principles of transformation was proposed. Accordingly, the available measuring sensors of alternating magnetic fields following to the group of used physical phenomena can be divided into: magnetomechanical, induction, galvanomagnetic, quantum, magneto-optical and photomagnetic. Depending on the characteristics of each of these phenomena, separate measurement methods and types of measuring sensors were highlighted. The current state of development of each of the types of measuring sensors of strength of alternating magnetic fields was analyzed, their advantages and disadvantages were determined, the limits of dynamic and frequency ranges, the maximum values of errors were outlined. The obtained results allow to significantly simplify and reduce the time of choosing the necessary method of strength (induction) of alternating magnetic fields measuring and to choose the necessary type of measuring sensor to effectively solve the tasks.