This paper considers Aircraft Landing Problem (ALP) in the context of optimal runway utilization. A heuristic algorithm is proposed to minimize a penalty cost function associated with the difference between the determined landing time and the target landing time. The objective is to obtain an optimal schedule for a sequence of a finite number of aircraft that can use 1, 2, or 3 runways. The constraints are defined in relation to the time window bounded by the earliest and latest landing times. Six single-objective simulation optimization tasks were solved, namely 2 tasks on 1 runway, one with sequences of 10 and the second with sequences of 20 aircraft, 2 tasks on 2 runways with sequences of 10 and 20 aircraft, respectively, and 2 tasks on 3 runways with sequences of 10 and 20 aircraft. The solutions found are optimal. The results show that the proposed algorithm has a good performance and can be used for solving real-life optimization problems of this type.
The production of glass fiber-reinforced polymer (GFRP) composite parts for engineering applications often requires drilling holes in these composite parts for assembling purposes. However, drilling can cause different types of part failure, one of those failures being delamination. The risk of delamination can be reduced by selecting appropriate technological parameters to ensure low cutting forces, that affect delamination. This paper presents the results of an experimental study investigating the relationship between cutting force and technological parameters of drilling (vc and fz) for GFRP composites. Four types of GFRP samples were used in the study, differing with respect to weight fraction ratio of a reinforcement material, fiber type (twill woven and plain woven) and manufacturing technology. A 2-edge carbide diamond coated drill with a diameter of 12.726 mm was used in the tests. Measurements of the cutting force component Fz in the drilling process conducted with variable technological parameters were made on a special test stand, 9257B from Kistler. Based on the study, it can be concluded that drilling conducted with lower values of technological parameters results in a lower value of the cutting force component Fz.
As human space exploration evolves toward longer voyages farther from our home planet, in-situ resource utilization (ISRU) becomes increasingly important. Haptic teleoperations are one of the technologies by which such activities can be carried out remotely by humans, whose expertise is still necessary for complex activities. In order to perform precision tasks with effectiveness, the operator must experience ease of use and accuracy. The same features are demanded to reduce the complexity of the training procedures and the associated learning time for operators without a specific background in robotic teleoperations. Haptic teleoperation systems, that allow for a natural feeling of forces, need to cope with the trade-off between accurate movements and workspace extension. Clearly, both of them are required for typical ISRU tasks. In this work, we develop a new concept of operations and suitable human-robot interfaces to achieve sample collection and assembly with ease of use and accuracy. In the proposed operational concept, the teleoperation space is extended by executing automated trajectories, offline planned at the control station. In three different experimental scenarios, we validate the end-to-end system involving the control station and the robotic asset, by assessing the contribution of haptics to mission success, the system robustness to consistent delays, and the ease of training new operators.
Additive technologies are increasingly used in the aerospace industry due to the possibility of producing lightweight, high-strength structures for aviation applications. However, this requires the use of appropriate testing procedures for structural elements relevant to the construction of aircraft. In the case of the PBF - Powder Bed Fusion technology, the properties of the products are related to the quality of the powder used during the 3D printing process. The article presents the analysis of the fatigue strength of models produced by the DMLS method in relation to the quality of the powder bed.
The paper presents the research experiment on deformations measurement of a wide-aperture antenna by the lidar system and the technique of data processing for the reconstruction of the reflective surface profile. The surface profile recovery algorithm of the antenna under investigation is described. Measurement of the reflector surface is performed with the help of a portable lidar system. 3D point cloud reconstruction and separation of the antenna surface coordinates are discussed. The reference surface is reconstructed at the base of a proposed mathematical model in order to evaluate the main antenna design parameters The mathematical model processes three-dimensional antenna surface coordinates extracted from a total cloud of lidar system scanning points. The objects of study were two mesh wide-aperture X and S-band antennas. The surface shape, symmetry error, and method performance of the investigated antenna was determined.
With increasing complexity of aircraft structures and demands for safety, structural health monitoring (SHM) systems are a frequently considered option to lower the cost and time consumption of aircraft maintenance. Recent advances in additive manufacturing techniques have enabled the fabrication of structures with artificially designed mechanical properties and the possibility to integrate smart materials directly into the structure. In this paper, we propose an innovative metamaterial structure with embedded piezoelectric transducers. The results show that the magnitude of the force applied to the structure can be determined from the electrical response of the transducers. A power of 5.9 mW was generated on a $400\ \mathrm{k}\Omega$ resistive load at an applied force of 11 N. The test sample shows the potential of the proposed structure for design of artificial structures and SHM systems in aerospace industry.
The thickness estimation of conductive plates is a crucial task in several application fields. Methods based on Eddy Current Testing (ECT) for thickness measurement involve several variables such as frequency, electrical conductivity, lift-off and probe geometry. The ECT thickness estimation depends on the quality of these variables knowledge and, typically, is based on time-consuming approaches that, needing multiple frequency measurements, deeply reduce their application in industrial scenarios. This paper focuses on the metrological characterization of a method previously developed by the authors and based on the application of the Buckingham's $\pi$ theorem to ECT for the simultaneous dual estimation of the thickness and electrical conductivity of conductive plates. In particular, the performance of the method was experimentally analyzed with respect to the stimulus ECT frequencies and to the features used for the estimation process of unknown thicknesses. The results showed the presence of an optimal set of frequencies in which the method can be applied using a single-frequency approach with good performance that, using the best feature for the thickness estimation, gives rise to a mean absolute relative error lower than 1.09%. The presented analysis opens the potentiality of the method to new performance challenges by adopting data fusion and double-frequencies techniques.
In this work, thermographic techniques have been demonstrated to be effective non-destructive testing (NDT) solutions for assessing the surface coating of components made from Ceramic Matrix Composites (CMC) ISiComp®. Developed by the Italian Aerospace Research Centre (CIRA) and PETROCERAMICS, ISiComp is an innovative CMC development of the Thermal Protection System for the ESA Space Rider Re-entry Module. The study aimed to identify the condition of the coating and categorize the samples as coated, uncoated or oxidized using different sources and methods of thermal excitation such us Pulsed Thermography, Lock-in Thermography and Pulsed Lock-in Thermography. The statistical analysis of the results shows that thermographic techniques are capable of distinguishing the three different coating conditions at a significance level of $\alpha=0.05$ .
The advantages of three degrees of freedom attitude measurement technology such as high measurement accuracy, long measurement distance, and large measurement range make it widely used in aerospace weapons. This article briefly describes the basic principles of the transfer alignment system in weapons and equipment, introduces the basic principles and system composition of the on-site calibration device for the reference light transfer system in response to the on-site testing and calibration requirements of the transfer alignment system in weapons and equipment, and analyzes the preliminary measurement results.
This work presents the functionality of a numerical code developed to simulate the Amplitude-dependent Single Optical Particle Counters working principle, aiming to assess the expected measurement uncertainty when the variability of the main interesting parameters is considered. The tool exploits Mie theory for light scattering to describe the interaction and the products of a collimated laser light enlightening aerosol particles. After the validation of the numerical code vs. a commercial software and literature data, the numerical tool was applied to a real case study, i.e., the MicroMED instrument, an Optical Particle Counter designed to operate on Mars. The detector output was simulated by exploiting firstly the nominal values for the light scattering quantities of interest, then accounting for the variability of the parameters with a Monte Carlo simulation. Thus, the designed numerical code represents either a valid support for Amplitude-dependent Single Optical Particle Counters calibration activities or for performing a feasibility study in brand new instruments' preliminary design phases.
This paper presents the measurement method and experimental results of a study investigating the effect of terrain obstacle geometry on the aircraft suspension system dynamics. Three different models of terrain obstacle geometry were tested: rectangular, triangular and semi-circular, each model having the same dimensions of 300×150×50mm. Experiments were conducted using the GOM PONTOS measuring system, which made it possible to perform a dynamic analysis of the suspension system of a Cessna 152 during passing over the above variable-geometry obstacles. All experiments were conducted for three takeoff runs of 1200, 1800 and 2700 millimetres for each terrain obstacle model, respectively. The study investigated the dynamic parameters of three crucial structural elements of the aircraft's suspension system: strut, fuselage and wheel centre, for which accelerations and velocities were measured when the aircraft was passing over the obstacles. The obtained test results indicate that the velocities $v$ of characteristic measurement points related to selected structural elements of the aircraft (fuselage, wheel, strut) vary in the range of 1.1-2.56 m/s when passing through various obstacles with different approach speeds (run-up speed). The acceleration values $\alpha$ change accordingly in the range 20–58 m/s 2 .
Optical fiber-based sensors have rapidly increased their application fields across multiple engineering sectors. Their physical characteristics, including low weight, electrical passivity, immunity to electromagnetic disturbances, and high sensitivity, make them highly suitable for aerospace applications. A flying test bench was recently developed at the Politecnico di Torino to evaluate the performance of optical sensors applied to an aircraft model. To allows their fruition in near real-time, it was necessary to develop a pipeline of software capable of transmitting, saving, and displaying them on the ground. To carry out in-depth tests on their reliability it is necessary to carry out more tests with different sensors and configurations. However, doing flight tests for the sole purpose of testing the data acquisition system is too expensive and impractical. Therefore, it was developed an emulator software that can generate data like that obtained from the real system, saving time and resources. Thanks to it, it is now possible to exploit the complete test bench on the aircraft for the final verification campaign only. The results are therefore very positive and demonstrate the potential of the emulator also for the most recent applications.
With the development of an increasingly datadriven global economy, the relevance of the space sector is increasing, with reference not only to the traditional telecommunications satellites but also to Earth Observation satellites, equipped with increasingly sophisticated electrooptical, radar and spectrographic payloads capable of collecting increasingly precise and well-defined data. This space race sees the participation above all of private entities that flank and sometimes replace the normal institutional players. However, private companies carry out extensive data collection, with the sole aim of making it profitable, while also increasing the number of satellites in orbit and also posing risks to the ecosystem. In this light, the aim of the paper is to specifically analyze the issue of personal data processing, also with regard to the latest advances in the field of sensors and access to space, adopting the tools of Empirical Legal Studies and cost-benefit assessment in order to identify the most appropriate intervention tool. The objective of the research study is to support a proposal for integrating space-related legislation with existing privacy legislation, in order to ensure effective protection of individuals.
This work discusses the effect of annealing heat treatment on deposited thin films for quartz crystal microbalances (QCMs), intended to be used for thermogravimetric analysis at high temperatures. The developed QCMs comprise embedded deposited resistors that can be employed either as heaters or temperature sensors, which are manufactured by particle vapor deposition of a bilayer of Ti-Pt microfilm. There is evidence in the literature that the annealing heating treatment affects the electrical resistance and the thermal coefficient of resistance (TCR) of this type of microfilm, especially in high-temperature ranges. It was found that for the analyzed conditions, i.e. with annealing temperatures varying between 250°C and $350^{\circ}\mathrm{C}$ , a general increase of the TCR is obtained, providing an improvement of the sensitivity of the resistors for the expected temperature measurement range.
This article highlights the importance of continuous flights and sustainable maintenance techniques to maintain competitiveness in the aviation industry. Structural components represent a significant portion of overall maintenance costs, and advanced nondestructive inspection techniques can help reduce maintenance time and associated costs. With the increasing use of composite structures in aircraft, it is essential to understand the possible types of defects that can occur and to use techniques the appropriate nondestructive techniques (NDT) for their identification and characterization. Comprehensive knowledge of possible defects and proper application of NDT techniques can help simplify maintenance operations and ensure sustainable and safe aircraft operations. The use of NDT techniques makes it possible to verify the quality of the composite material and identify any defects. This allows timely action to correct any problems and ensure maximum reliability and durability of the material. In this context, this paper provides a comparison of several techniques as nondestructive methods on a sample of interest to the aerospace industry and evaluates the parameters of their use: shearography, thermography and ultrasound.
Main subject of the work is the characterization of an enclosed environment representative of future lunar habitats in terms of microwave chaotic propagation, focusing on how the EM scattering and absorption comes to be affected by the increasing of moisture level within the inner atmosphere. The rationale of the study lies in a wider research project which aims at performing a Moon feasibility investigation in terms of using lunar soil (regolith) for cultivation and building purpose, as well as to identify possible interferences for TLC systems due to its specific mineral and chemical composition. Thus, the issue of the influence of humidity on the microwave behavior detected inside regolith-based infrastructures should be worth of investigation, especially if remote monitoring and controlling operations to run a space farming greenhouse are envisaged. The study is performed by means of a space environment simulator connected to a microwave characterization equipment in order to evaluate the electromagnetic field attenuation inside a reverberating chamber in the range 1–6 GHz: the several materials and structures filling the chamber are conceived on the base of literature data regarding the lunar regolith composition, while the atmosphere conditions - in terms of pressure, temperature and moisture - are set-up to assess the dependence of the chamber microwave absorbing effectiveness on the varying environmental parameters. The preliminary measurements show that the effects of the surroundings on the microwave propagation must be strictly taken into account in order to design efficiently mobile telecommunications systems operating inside lunar habitats.
Unmanned aerial vehicles (UAVs) have drawin increasing attention in recent years, and they are widely applied. Nevertheless, they are generally limited by poor flight endurance because of the limited energy density of their batteries. A robust power supply is indispensable for advanced UAVs; thus hybrid power might be a promising solution. State of charge (SOC) estimation is essential for the power systems of UAVs. The limitations of accurate SOC estimation can be partly ascribed to the inaccuracy of open circuit voltage (OCV), which is obtained through specific forms of identification. Considering the actual operation of a battery under hybrid conditions, this paper proposes a novel method, "fast OCV", for obtaining the OCVs of batteries. It is proven that fast OCV offers great advantages, related to its simplicity, duration and cost, over traditional ways of obtaining OCV. Moreover, fast-OCV also shows better accuracy in SOC estimation than traditional OCV. Furthermore, this paper also proposes a new method, "batch mode", for talking-data sampling for battery-parameter identification with the limited-memory recursive least-square algorithm. Compared with traditional the "single mode", it presents good de-noising effect by making use of all the sampled battery's terminal current and voltage data.
Recent progress in manufacturing techniques has led to a wide range of new materials and components. Advance in material development has resulted in a wide range of new kind of materials as carbon composite and carbon fiber reinforced. The need, already consolidated, to investigate its properties (mechanical, electrical, thermal, etc.) arises and characterize the possible innovations by industrial sector such as aeronautics and aerospace, through the use of analysis techniques non-destructive (NDT). Common NDT techniques can be classified into seven major categories: visual (visual inspection), penetrating radiation (X-ray, and neutron imaging), magnetic-electrical (magnetic particle), mechanical vibration (ultrasonic, acoustic emission, and tapping), chemical/electrochemical (chemical spot testing), thermal (infrared thermography) and other optical methods (interferometry, holography, and shearography). More traditional non-destructive techniques (NDT) are not always effective as expected, and there is therefore a long-term need to use innovative NDT methods capable of provide reliable and quantitative information regarding damage status and integrity of materials. In the present work we focus on the development of specific tools of NDT for assuring the quality related to the fabrication of industrial components. The potential tool that will be take into consideration for inspection and detection of defects will mainly based on the following two main methods: ‐full-field optical techniques (such as profilometry, interferometry, sherography and thermography); ‐Laser ultrasound testing (LUT); The integrated and combinated use of different NDT (thermography, shearography and ultrasound) was necessary for a complete characterization of some types of composite materials.
Nowadays the use of GNSS Spaceborne Receiver for GEO missions is proving to be a realistic alternative solution in the Space application market. In particular in GEO missions or above the knowledge of an accurate GNSS spacecraft attitude dynamic in space became essential for supporting the space missions and application based on the high-precision and accuracy GNSS navigation (i.e. low C/N 0 ). In fact, the GNSS satellites attitude model is strictly linked to the considered geometrical measurement model at the transmitter phase center location and carrier phase measurements. A complete knowledge and GNSS attitude modelling can also help future GNSS Receiver implementation for the newest moon missions in which an high sensitivity signal processing is requested. In this paper additional in-flight data analysis are shown as well as the GPS and GALILEO antenna patterns reconstruction in elevation and azimuth thanks to the GNSS yaw-steering model processing.
This work deals with the application of a DoE based optimization approach in order to estimate XCT parameters configuration quantitatively for three different kinds of composite materials in function of scan contrast-to-noise ratio measurement. These are carbon fiber, glass fiber and flax fiber reinforced epoxy composite materials. An analysis of actual densities of these scanned components, which resulted to be 1.53, 1.96 and 1.29 g/cm 3 respectively, was useful to understand how much their variations, together with the percentage of inner detected anomalies, were linked to the optimal XCT parameters selected from DoE. These turned out to involve an X-ray source voltage of 120 kV for carbon and glass fiber ones, while 115 k V for flax fiber one.
