Showing papers on "Landing gear published in 2018"
TL;DR: In this article, a simplified landing gear assembly model was created to complement with an accurate slave link subassembly, generated based of drawings supplied from the industrial partner, Safran Landing Systems.
Abstract: Aircraft landing gear assemblies comprise of various subsystems working in unison to enable functionalities such as taxiing, take-off and landing. As development cycles and prototyping iterations begin to shorten, it is important to develop and improve practical methodologies to meet certain design metrics. This paper presents an efficient methodology that applies high-fidelity multi-disciplinary design optimization techniques to commercial landing gear assemblies, for weight, cost, and structural performance by considering both structural and dynamic behaviours. First, a simplified landing gear assembly model was created to complement with an accurate slave link subassembly, generated based of drawings supplied from the industrial partner, Safran Landing Systems. Second, a Multi-Body Dynamic (MBD) analysis was performed using realistic input motion signals to replicate the dynamic behaviour of the physical system. The third stage involved performing topology optimization with results from the MBD analysis; this can be achieved through the utilization of the Equivalent Static Load Method (ESLM). Lastly, topology results were generated and design interpretation was performed to generate two designs of different approaches. The first design involved trying to closely match the topology results and resulted in a design with an overall weight savings of 67%, peak stress increase of 74%, and no apparent cost savings due to complex features. The second design focused on manufacturability and achieved overall weight saving of 36%, peak stress increase of 6%, and an estimated 60% in cost savings.
46 citations
14 Feb 2018
TL;DR: The results of the experiments show that the DroneGear can be successfully used for the safe hexacopter landing on the different angle slopes, plane, step surfaces, and for terrain profile estimation as well.
Abstract: One of the most serious disadvantages of the vertical takeoff and landing flying robots including multicopters is the necessity of the flat stable area for safe landing. The ability to land and takeoff from uneven surfaces and moving basements would help the rotorcrafts in many important applications. The special landing gears are used to provide rotorcrafts this ability. This letter explores multicopter landing on uneven surfaces using a novel adaptive landing platform DroneGear. The DroneGear contains four compliant robotic legs of two degrees of freedom each. The innovative optical torque sensor is integrated into the knee joint of each leg to provide timely adaptation to rough terrain in an unknown environment. Additionally, inertial measurement unit is embedded into the passive footpad of each leg for estimation of relief profile in the landing zone. The results of the experiments show that the DroneGear can be successfully used for the safe hexacopter landing on the different angle slopes, plane, step surfaces, and for terrain profile estimation as well.
42 citations
27 Feb 2018
TL;DR: In this paper, the authors propose a perception system to detect landing sites based on their texture and geometric shape without using any prior knowledge about the environment, and a safe approach path is computed based on the UAV dynamics, expected state estimation and actuator uncertainty, and the on-board computed elevation map.
Abstract: Full autonomy for fixed-wing unmanned aerial vehicles (UAVs) requires the capability to autonomously detect potential landing sites in unknown and unstructured terrain, allowing for self-governed mission completion or handling of emergency situations. In this letter, we propose a perception system addressing this challenge by detecting landing sites based on their texture and geometric shape without using any prior knowledge about the environment. The proposed method considers hazards within the landing region such as terrain roughness and slope, surrounding obstacles that obscure the landing approach path, and the local wind field that is estimated by the on-board EKF. The latter enables applicability of the proposed method on small-scale autonomous planes without landing gear. A safe approach path is computed based on the UAV dynamics, expected state estimation and actuator uncertainty, and the on-board computed elevation map. The proposed framework has been successfully tested on photo-realistic synthetic datasets and in challenging real-world environments.
29 citations
TL;DR: In this article, a magnetorheological (MR) damper for the landing gear system of airplanes is presented, which is used for the first time in the history of the world.
Abstract: In this research, a new type of magnetorheological (MR) damper, applicable to the landing gear system of airplanes, is presented. As a first step, an oleo-pneumatic damper, which is used for the la...
26 citations
TL;DR: In this paper, a detailed model of the nose section of a 90-seat configuration green regional aircraft concept was built and a nose landing-gear test campaign was conducted to evaluate its performance.
Abstract: This paper presents experimental results from a nose landing-gear test campaign. A highly detailed model of the nose section of a 90-seat configuration green regional aircraft concept was built and...
25 citations
25 Jun 2018
TL;DR: A series of flight tests targeting airframe noise reduction was planned and executed under the NASA Flight Demonstrations and Capabilities project as discussed by the authors, where an Adaptive Compliant Trailing Edge flap, main landing gear fairings, and gear cavity treatments were integrated on a NASA Gulfstream G-III aircraft to determine their effectiveness, both on a componentlevel (individually) and a system-level (combined) basis.
Abstract: A series of flight tests targeting airframe noise reduction was planned and executed under the NASA Flight Demonstrations and Capabilities project. The objectives of the tests were two-fold: to evaluate the aeroacoustic performance of several noise reduction technologies in a relevant environment and to generate a comprehensive database for advancing the state of the art in simulation-based airframe noise prediction methodologies. These technologies – an Adaptive Compliant Trailing Edge flap, main landing gear fairings, and gear cavity treatments – were integrated on a NASA Gulfstream G-III aircraft to determine their effectiveness, both on a component-level (individually) and a system-level (combined) basis. With the aircraft flying an approach pattern and the engines set at ground idle, extensive acoustic measurements were acquired using a phased microphone array system. Detailed analyses of the gathered acoustic data clearly demonstrate that significant noise reduction was achieved for the flap and main landing gear components.
21 citations
05 Apr 2018
TL;DR: The measurement of ultra-high frequency RFID tags on an aircraft landing gear using an aircraft-mounted fixed RFID reader indicates that all major landing gear components and assemblies are shown to be identifiable by their EPC, and a 7 dB system margin has been achieved using 2RFID reader antennas.
Abstract: Radio frequency identification (RFID) has been used in the aviation industry to track and identify emergency equipment and other in-cabin assets on commercial aircraft for some time. Recently, the industry is looking to expand the use of RFID to more demanding parts and surfaces both inside and outside of an aircraft’s cabin, where RFID tags face much harsher conditions. The landing gear (LG) is one of the critical subsystems of an aircraft that plays an essential role in dispersing the energy of landing events and taxiing. Health monitoring of the LG has been suggested to help reduce both operational and maintenance costs, and extend the life of the LG beyond its current, fixed, designed service life. In this paper, we propose a health monitoring system using a combination of active wired sensors and passive RFID tags. We present the measurement of ultra-high frequency RFID tags on an aircraft landing gear using an aircraft-mounted fixed RFID reader. The results indicate that all major landing gear components and assemblies are shown to be identifiable by their EPC, and a 7 dB system margin has been achieved using 2 RFID reader antennas. Such a margin will tolerate degradations caused by harsh environments (e.g., low temperatures and high humidity) and enable update of information (e.g., flight count) stored on the RFID tags.
20 citations
TL;DR: In this article, the LAGOON landing gear configuration is performed using different unstructured meshes, and one mesh is generated based on available experimental and numerical data, and b...
Abstract: Detached-eddy simulations of the LAGOON landing gear configuration are performed using different unstructured meshes. One mesh is generated based on available experimental and numerical data, and b...
20 citations
01 Oct 2018
TL;DR: An adaptive landing gear is proposed that consists of four legs with one degree of freedom each, composed of a parallel arrangement of motor and brake, which relieves the motor from large impact loads during hard landings.
Abstract: Conventional skid or wheel based helicopter landing gears severely limit off-field landing possibilities, which are crucial when operating in scenarios such as mountain rescue. In this context, slopes beyond 8° and small obstacles can already pose a substantial hazard. An adaptive landing gear is proposed to overcome these limitations. It consists of four legs with one degree of freedom each. The total weight was minimized to demonstrate economic practicability. This was achieved by an innovative actuation, composed of a parallel arrangement of motor and brake, which relieves the motor from large impact loads during hard landings. The loads are alleviated by a spring-damper system acting in series to the actuation. Each leg is individually force controlled for optimal load distribution on compliant ground and to avoid tipping. The operation of the legs is fully autonomous during the landing phase. A prototype was designed and successfully tested on an unmanned helicopter with a maximum take-off weight of 78 kg. Finally, the implementation of the landing gear concept on aircraft of various scales was discussed.
17 citations
01 Jan 2018
TL;DR: In this article, a full-scale nose landing gear, measured in a wind tunnel and obtained from computational simulations, is compared with those of three regional aircraft types recorded in flyover measurements.
Abstract: The noise emissions of a full-scale nose landing gear, measured in a wind tunnel and obtained from computational simulations, are compared with those of three regional aircraft types recorded in flyover measurements. The results from these three approaches are also compared with the predictions of two airframe noise models (Fink and Guo). The geometries of the nose landing gears in all cases were similar. Microphone arrays and acoustic imaging algorithms were employed to estimate the sound emissions of the nose landing gears. A good agreement was found between the overall trends of the frequency spectra in all cases. Moreover, the expected 6th power law with the flow velocity was confirmed. On the other hand, strong tonal peaks (at around 2200 Hz) were only found for the flyover tests and computational simulations and are not present in typical noise prediction models. As the frequencies of the tones did not depend on the flow velocity, they are likely to be caused by cavities found in structural components of the nose landing gear. Removing these tones would cause overall noise reductions up to 2 dB in the frequency range examined. The noise emissions in the side direction did not present tonal peaks. The acoustic source maps showed that the dominant noise sources were located in the middle of the wheel axle, followed by the main strut and the bay doors. It is, therefore, recommended to further investigate this phenomenon, to include cavity-noise estimations in the current noise prediction models, and to eliminate such cavities where possible with the use of cavity caps, for example.
17 citations
TL;DR: In this article, the authors proposed a new method for reducing the shock vibration response of an UAV during the landing process by means of the momentum exchange principle (MEID), which reduced the impact of the UAV's impact on the ground.
Abstract: This study proposes a new method for reducing the shock vibration response of an Unmanned Aerial Vehicle (UAV) during the landing process by means of the momentum exchange principle (MEID). The per...
TL;DR: The good agreement between the simulated model and RS- model results are obtained in two optimized designs, which show that the RS-model coupled with the FE (finite element)-method is an efficient method to obtain the design configuration of the landing gear.
TL;DR: Two non-coplanar spatial six-bar linkages are creatively designed to generate double-lock loading configuration with redundant constraints to achieve higher stiffness, higher strength and higher reliability for a landing gear system.
01 Oct 2018
TL;DR: In this article, uncertain polytopic state space representation is developed by modelling the pneumatic shock absorber dynamics as a mechanical system with non-linear stiffness and damping properties, and a linear matrix inequalities-based robust linear quadratic regulator controller having pole location constraints is designed, since the classical linear quadric regulator control design is dealing with linearized state space models without considering the nonlinearities and uncertainties.
Abstract: This paper deals with the active control of a non-linear active landing gear system equipped with oleo pneumatic shock absorber. Runway induced vibration can cause reduction of pilot’s capability of control the aircraft and results the safety problem before take-off and after landing. Moreover, passenger–crew comfort is adversely affected by vertical vibrations of the fuselage. The active landing gears equipped with oleo pneumatic shock absorber are highly non-linear systems. In this study, uncertain polytopic state space representation is developed by modelling the pneumatic shock absorber dynamics as a mechanical system with non-linear stiffness and damping properties. Then, linear matrix inequalities-based robust linear quadratic regulator controller having pole location constraints is designed, since the classical linear quadratic regulator control design is dealing with linearized state space models without considering the non-linearities and uncertainties. Thereafter, numerical simulation studies ar...
12 Jun 2018
TL;DR: A previously designed dynamic model of the landing gear is extended with the experimental characterization of the hydraulic braking system, and a test-rig is setup, which allows testing the contact between wheel and ground with a flywheel.
Abstract: Aircraft control systems are in general difficult to test in their final deployment phases, as flight time has very high costs and entails possible dangerous working conditions. Thus, coming to test flights with control algorithms that have been thoroughly tested beforehand is paramount. As far an anti-skid control is concerned, the industrial practice is to have the anti-skid controller embedded in the landing gear, so that the initial test bench for controller design is a rig comprising all or parts of the landing gear system. In this work, we extend a previously designed dynamic model of the landing gear with the experimental characterization of the hydraulic braking system. Then, a test-rig is setup, which allows testing the contact between wheel and ground with a flywheel. Open-loop experiments to tune the simulator are conducted, and a final validation of the simulation model against experimental data is carried out.
25 Jun 2018
TL;DR: In this article, the simulation results for a full-scale simulation of a Gulfstream G-III aircraft were presented, and the simulation campaign for the baseline aircraft configuration at several flight conditions was described.
Abstract: Computational results for a full-scale simulation of a Gulfstream G-III aircraft are presented. In support of a NASA airframe noise flight test campaign, Exa Corporation’s lattice Boltzmann PowerFLOW® solver was used to perform time-accurate simulations of the flow around a highly detailed, full-scale aircraft model. Free-air boundary conditions were used at a Mach number of 0.23 and a Reynolds number of 10.5 × 10(exp 6) based on mean aerodynamic chord. This paper documents the simulation campaign for the baseline aircraft configuration at several flight conditions, including multiple flap deflections and main landing gear deployed or retracted. The high-fidelity, synthetic data were post-processed using a Ffowcs-Williams and Hawkings integral approach to estimate farfield acoustic behavior, with pressures on the model solid surface or a permeable surface enveloping the acoustic near field used as input. The numerical approach, simulation attributes, and the effects of grid resolution, gear deployment, and multiple flap deflections, are discussed as well.
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TL;DR: This letter proposes a perception system addressing this challenge by detecting landing sites based on their texture and geometric shape without using any prior knowledge about the environment by considering hazards within the landing region such as terrain roughness and slope.
Abstract: Full autonomy for fixed-wing unmanned aerial vehicles (UAVs) requires the capability to autonomously detect potential landing sites in unknown and unstructured terrain, allowing for self-governed mission completion or handling of emergency situations. In this work, we propose a perception system addressing this challenge by detecting landing sites based on their texture and geometric shape without using any prior knowledge about the environment. The proposed method considers hazards within the landing region such as terrain roughness and slope, surrounding obstacles that obscure the landing approach path, and the local wind field that is estimated by the on-board EKF. The latter enables applicability of the proposed method on small-scale autonomous planes without landing gear. A safe approach path is computed based on the UAV dynamics, expected state estimation and actuator uncertainty, and the on-board computed elevation map. The proposed framework has been successfully tested on photo-realistic synthetic datasets and in challenging real-world environments.
TL;DR: In this article, three numerical models of the main landing gear of a regional airliner have been developed, according to MB, "stick,” and 3D full-FE methods, respectively.
Abstract: Usually during the design of landing gear, simplified Finite Element (FE) models, based on one-dimensional finite elements (stick model), are used to investigate the in-service reaction forces involving each subcomponent. After that, the design of such subcomponent is carried out through detailed Global/Local FE analyses where, once at time, each component, modelled with three-dimensional finite elements, is assembled into a one-dimensional finite elements based FE model, representing the whole landing gear under the investigated loading conditions. Moreover, the landing gears are usually investigated also under a kinematic point of view, through the multibody (MB) methods, which allow achieving the reaction forces involving each subcomponent in a very short time. However, simplified stick (FE) and MB models introduce several approximations, providing results far from the real behaviour of the landing gear. Therefore, the first goal of this paper consists of assessing the effectiveness of such approaches against a 3D full-FE model. Three numerical models of the main landing gear of a regional airliner have been developed, according to MB, “stick,” and 3D full-FE methods, respectively. The former has been developed by means of ADAMS® software, the other two by means of NASTRAN® software. Once this assessment phase has been carried out, also the Global/Local technique has verified with regard to the results achieved by the 3D full-FE model. Finally, the dynamic behaviour of the landing gear has been investigated both numerically and experimentally. In particular, Magnaghi Aeronautica S.p.A. Company performed the experimental test, consisting of a drop test according to EASA CS 25 regulations. Concerning the 3D full-FE investigation, the analysis has been simulated by means of Ls-Dyna® software. A good level of accuracy has been achieved by all the developed numerical methods.
25 Jun 2018
TL;DR: The hardware development, ground operations, and flight operations which went into acquiring the desired acoustic measurements were provided, and in general, the flights were successful and demonstrated the noise reduction benefits of the ACTE flaps, the LAGER gear fairings, and the L AGER gear cavity treatments.
Abstract: The National Aeronautics and Space Administration (NASA) Acoustic Research Measurements (ARM) project was established to evaluate via flight tests the noise reduction benefits of the Adaptive Compliant Trailing Edge (ACTE) technology along with various main landing gear noise reduction concepts. The ACTE replaces the original Fowler flaps on the NASA SubsoniC Research Aircraft Testbed (SCRAT), thus creating a seamless trailing edge that provides significant noise abatement benefits. The various main landing gear noise reduction concepts are grouped under the LAnding Gear noisE Reduction (LAGER) task and consist of fairings placed on the main landing gear along with two separate treatments applied to the main landing gear wheel well cavities. This paper discusses the tasks necessary to prepare each of these technologies for the ARM flights. The LAGER hardware was taken from model-scale concepts tested in wind tunnels to flight hardware, which had to be cleared as airworthy for the ARM flights. The ACTE flaps were initially intended to be removed from the SCRAT prior to the start of the ARM project. Retaining the ACTE flaps on the aircraft for a longer period of time to support the ARM flights resulted in additional inspections and considerations since the ACTE flaps were flown longer and at certain flight conditions for longer periods of time than initially analyzed. The flight and ground operations required for the ARM tests required extensive coordination among multiple groups and organizations in order to be successful. This paper provides an overview of the hardware development, ground operations, and flight operations which went into acquiring the desired acoustic measurements. In general, the flights were successful and demonstrated the noise reduction benefits of the ACTE flaps, the LAGER gear fairings, and the LAGER gear cavity treatments.
25 Jun 2018
Patent•
12 Oct 2018
TL;DR: In this paper, the authors described an aircraft landing gear consisting of an upper fixing part, a sliding part, and a rotating shaft with two frictiondiscs, and the friction discs correspondingly located on both sides of the sliding part.
Abstract: The invention discloses an aircraft landing gear. The aircraft landing gear comprises an upper fixing part, a sliding part, a rotating shaft and tires. The rotating shaft is provided with two frictiondiscs, and the friction discs are correspondingly located on both sides of the sliding part. The upper fixing part is provided with cover shells at positions relative to the friction discs, and friction plates are fixed in the cover shells. When the sliding part slides upwards along the side wall of a blind hole, the friction discs and the friction plates are in contact with each other. When theaircraft landing gear is used, predetermined gaps exist between the friction discs and the friction plates in the conventional state. When an aircraft lands, the sliding part slides upwards and enablesprings to be compressed, the friction discs and the friction plates are in contact with each other at this time to slow down the aircraft, when the aircraft uses an air brake to slow down, a fuselage can generate downward pressure, and the friction discs and friction plates can further be in contact with each other at this time to enable the aircraft to slow down. When the speed of the aircraftdrops to a certain threshold, the springs force the sliding part to reset and separate the friction discs from the friction plates.
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TL;DR: This paper relies on theoretical proposition of practical design of landing gear system and expects that, subject to any obstruction in EDL sequence, this mechanical system will enable soft-landing thereby increasing the probability of success in forthcoming landing missions.
Abstract: Landing robotic spacecrafts and humans on the surface of Mars has become one of the inevitable technological necessity for humans. To accomplish this intention, we need to land enormous number of cargoes, crewed modules, return vehicles and scientific laboratories on Mars. In this entailing condition, there are many incidences of crash landing leading to complete demolition of lander modules. Crash landing occurs under numerous circumstances. Significant problems were loss of communication, onboard command error, lander malfunction, software problem and premature EDL performance. Moreover, existence of deformable shock absorbers like Aluminium honeycomb and crushable carbon fibers in landing gears are not feasible for high scale mass and crewed landing. Consequently, it may cause impairment of landing module. Further, while evaluating the interim EDL performance, landing and switching EDL events within a limited span of 5 to 8 minutes appears to be the most challenging task. Scrutinizing this concern, we propose a novel shock absorbing landing gear system that will be more achievable for large scale and frequent landing missions. This paper relies on theoretical proposition of practical design of landing gear system and we expect that, subject to any obstruction in EDL sequence, this mechanical system will enable soft-landing thereby increasing the probability of success in forthcoming landing missions. Hence, our ultimate aim is to protect lander modules and their instruments during the course of landing.
01 Jan 2018
TL;DR: In this paper, a tensor product model transformation (TPMT) and twisting sliding mode algorithm (TSMA) are utilized to design a robust controller for suppression of the shimmy vibration.
Abstract: Shimmy vibration is a common phenomenon in landing gear systems during either the take-off or landing of aircrafts. The shimmy vibration is undesirable since it can damage the landing gear and discomforts the pilots and passengers. In this work, tensor product model transformation (TPMT) and twisting sliding mode algorithm (TSMA) are utilized to design a robust controller for suppression of the shimmy vibration. The design has two steps. First, the TPMT is applied to determine the first part of the controller to suppress the vibration of the undisturbed system. After that, the TSMA is adopted to obtain another part of the controller to eliminate the remaining vibration caused by disturbances. By integrating these two parts, the proposed controller is obtained. Simulation studies are provided to demonstrate the effectiveness of the controller.
23 Oct 2018
TL;DR: The German Aerospace Center (DLR) has developed the assistance system LNAS (Low Noise Augmentation System), a software solution using flight data provided by a common interface aboard a passenger aircraft to assist pilots to realize low-noise and more efficient approaches.
Abstract: In order to assist pilots to realize low-noise and more efficient approaches, the German Aerospace Center (DLR) has developed the assistance system LNAS (Low Noise Augmentation System). It is a software solution using flight data provided by a common interface aboard a passenger aircraft. Recommendations are visualized on the Electronic Flight Bag (EFB) in the cockpit by an intuitive energy-based Vertical Situation Display (VSD) which also indicates the optimal points in time to perform the different actions like setting of speeds, flaps, landing gear and if necessary speed brakes. During approach a continuous correction is carried out to provide the energy-optimal profile at any time, even if the predicted approach changes e.g. due to a variation of ground wind conditions.
Patent•
31 May 2018
TL;DR: In this article, a vertical take-off and loading (VTOL) rotary aircraft or helicopter has eight propellers in a quad-probeller arm configuration where each propeller arm has two counter-rotating propellers.
Abstract: A vertical take-off and loading (VTOL) rotary aircraft or helicopter has eight propellers in a quad propeller arm configuration where each propeller arm has two counter-rotating propellers. Folding propeller arms are designed to allow storage in a single car sized garage. Each propeller may be powered by a three-phase alternating current motor. The main power plant for the aircraft is a gas combustion engine that generates electricity. If the gas engine fails, a battery backup system will safely bring the aircraft down for a controlled landing. The direct current bus is redundant in that even with a gas combustion engine failure the direct current bus battery pack will safely bring down the aircraft. Various embodiments of this invention may also include a landing gear crumple zone designed to soften a hard landing.
24 Jul 2018
TL;DR: The conceptual design and a preliminary sizing of landing gear structural components and actuation systems are presented, in order to get an estimation of weight and of the required stowage.
Abstract: The subject of the present paper is the design of an innovative fuselage mounted main landing gear, developed for a PrandtlPlane architecture civil transport aircraft with a capacity of about 300 passengers. The paper presents the conceptual design and a preliminary sizing of landing gear structural components and actuation systems, in order to get an estimation of weight and of the required stowage. The adopted design methodology makes use of dynamic modelling and multibody simulation from the very first design stages, with the aim of providing efficient and flexible tools for a preliminary evaluation of performances, as well as enabling to easily update and adapt the design to further modifications. To develop the activity, the multibody dynamics of the landing gear (modelled using Simpack software) has been integrated via co-simulation with dynamic models developed in the Matlab/Simulink environment.
01 Jan 2018
TL;DR: In this article, the ITEMB team in the contest of the Clean Sky 2 framework, with the scope of a new architecture for the Main Landing Gear of a single isle aircraft type, presents its development in designing the two major item of the main landing gear bay that are the roof and the rear pressure bulkhead using pre-preg CFRP material.
Abstract: In this paper, ITEMB team in the contest of the Clean Sky 2 framework, with the scope of a new architecture for the Main Landing Gear of a single isle aircraft type, presents its development in designing the two major item of the Main Landing Gear Bay that are the “roof” and the “rear pressure bulkhead” using pre-preg CFRP material. Typically, a lot of parts (metallic and also composite made) are involved in the two items manufacturing: the research effort has targeted the design of one piece structures consisting in a monolithic “roof” and “monolithic “rear pressure bulkhead”. The assembly of these ones takes advantages from a hole-tohole assembly supported by statistical analysis. The main expected advantages are the reduction of: both non-recurring and recurring cost, the overall flow time and weight saving. The ITEMB (InTEgrated Main landing gear Box) team has worked adapting a bag-to-bag technology to the geometrical and strength capability requirements of the component and outcome of the research (not yet concluded at time of issuing this paper) includes: A design principle supported by stress analysis for strength, stability and local main load introduction; A manufacturing trials campaign to reach the possess of a robust process; A limited coupons test campaign to demonstrate that no specific critical items exists in the design approach. Finally, participants have acquired a new design and manufacturing technique, applicable also to other Aircraft components upgrading their capabilities and European strength in composite structures manufacturing.
30 Jun 2018
TL;DR: In this paper, nonlinear vibration analysis of a typical aircraft oleo pneumatic landing gear has been done and results obtained have close agreement with the results obtained from ABAQUS.
Abstract: In this paper, nonlinear vibration analysis of a typical aircraft oleo pneumatic landing gear has been done. Mathematical model of the main landing gear is developed, and dynamic equations have been written incorporating the effect of lift force, friction force to study the landing gear behaviour at touchdown condition. The nonlinear effect of stiffness, damping coefficient properties are considered in the analysis. The displacement, velocity, acceleration values are obtained on different landing velocities by numerical simulations using MATLAB/Simulink. Using the same parameters of the aircraft, landing gear and tire, the dynamic analysis was also done in ABAQUS. The results obtained by the nonlinear vibration analysis using the developed model in MATLAB/Simulink have close agreement with the results obtained from ABAQUS. On the basis of the presented model, dynamic simulations of landing for large transport aircraft were performed for different sink velocities. The developed model is also helpful to fine tune the stiffness and damping properties of landing gear in the design stage itself to reduce the replacement / repair cost and increase the life of landing gear assembly.
TL;DR: The maximum horizontal impact load experienced by an aircraft's landing gear wheel during landing is an important parameter in the landing gear's safety design and performance analysis using a non-linear model as mentioned in this paper.
Abstract: The maximum horizontal impact load experienced by an aircraft's landing gear wheel during landing is an important parameter in the landing gear's safety design and performance analysis. Using a non...
Patent•
20 Sep 2018
TL;DR: In this paper, a method and apparatus for autonomous control of UAVs is presented, which includes, in a memory of a flight controller associated with an unmanned aircraft, identifying a target to be captured, the identifying comprising a plurality of target variables, selecting one or more capture routines, defining desired data parameters, and storing the plurality of targets and the desired data parameter in the memory as a flight path.
Abstract: A method and apparatus for autonomous control of unmanned aircraft. A method includes, in a memory of a flight controller associated with an unmanned aircraft, identifying a target to be captured, the identifying comprising a plurality of target variables, identifying a type of the unmanned aircraft, selecting one or more capture routines, defining desired data parameters, and storing the plurality of target variables, the one or more capture routines and the desired data parameters in the memory as a flight path. A system includes a computing device having at least a processor, a memory and a display, the display including a graphical user interface (GUI), and an unmanned aircraft including at least a flight controller, a power supply, a propeller system, a landing gear system, a Global Positioning System (GPS) device, a camera system and a one or more sensors, the flight controller wirelessly linked to the computing device which provides flight path control information to the flight controller through the GUI.