Friction analysis of aircraft landing gears due to landing impact

2021 ◽  
pp. 135065012110208
Author(s):  
Sanjay Baskaran ◽  
Sivakumar Sivaprakasam
Keyword(s):  
Degrees Of Freedom ◽  
Frictional Resistance ◽  
Landing Gear ◽  
Design Stage ◽  
Friction Forces ◽  
Six Degrees Of Freedom ◽  
Aircraft Landing ◽  
Landing Impact ◽  
Landing Gears ◽  
Friction Analysis

In this work, a six degrees of freedom heave-pitch mathematical model has been developed for an aircraft with main and nose oleo-pneumatic landing gear. Nonlinearities in stiffness, damping, and bending characteristics of landing gears and tires are incorporated in the model. Friction is an incidental and inevitable reaction that sticks along with the strut motion during the event of ground contact. The friction generated in the landing gear is the sum of the contribution from bearings and seals fitted in the landing gear. This study has focused on investigating the amount of frictional resistance gained by the struts while an aircraft is landing at various sink rates. The strut vertical forces, seal friction forces, and bearing friction forces generated in the main and nose landing gear during touchdown have been presented in this work. This preliminary estimation of friction forces for a range of sink rates aids the designer in developing optimal geometric or strut parameters in the design stage. This work also helps to calculate total landing loads for the certification of the landing gear.

scholarly journals Control of shimmy vibration in aircraft landing gears based on tensor product model transformation and twisting sliding mode algorithm

2018 ◽  
Vol 161 ◽  
pp. 02001 ◽  
Author(s):  
Suwat Kuntanapreeda
Keyword(s):  
Tensor Product ◽  
Model Transformation ◽  
Sliding Mode ◽  
Landing Gear ◽  
Common Phenomenon ◽  
Simulation Studies ◽  
Product Model ◽  
Robust Controller ◽  
Aircraft Landing ◽  
Landing Gears

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.

Landing efficiency control of a six degrees of freedom aircraft model with magneto-rheological dampers: Part 2—control simulation

2020 ◽  
pp. 1045389X2094259
Author(s):  
Byung-Hyuk Kang ◽  
Ji-Young Yoon ◽  
Gi-Woo Kim ◽  
Seung-Bok Choi
Keyword(s):  
Degrees Of Freedom ◽  
Maximum Energy ◽  
Control Logic ◽  
Six Degrees Of Freedom ◽  
Aircraft Landing ◽  
Efficiency Control ◽  
Model Equations ◽  
Magneto Rheological ◽  
The Time Domain ◽  
Distinct Features

In Part 1 of this work, both the kinematic and dynamic equations of aircraft landing model integrated with magneto-rheological damper were derived. In Part 2, the landing efficiency is analyzed through landing motion simulation which is performed on the basis of the model equations derived in Part 1. To investigate the landing efficiency with respect to the operating force control of magneto-rheological fluid, two different control logics for magneto-rheological damper are designed. The first one is the skyhook controller, which is known to be simple, but very effective for the semi-active control system. In this control logic, the switching condition depending on the compression and extension mode of the damper is determined to achieve maximum energy dissipation. The second one is a modified skyhook controller associated with the semi-active bouncing control. This controller is introduced to prevent bouncing of the main landing gear tires and to reduce the roll motion of the aircraft. The landing efficiency is evaluated at several rates of descent, and its distinct features such as tire displacement and pitch angle are compared in the time domain.

Geometric Error Effects on Manipulators' Positioning Precision: A General Analysis and Evaluation Method

2016 ◽  
Vol 8 (6) ◽  
Author(s):  
Henrique Simas ◽  
Raffaele Di Gregorio
Keyword(s):  
Degrees Of Freedom ◽  
Evaluation Method ◽  
Geometric Error ◽  
Design Stage ◽  
Positioning Precision ◽  
Six Degrees Of Freedom ◽  
Analysis And Evaluation ◽  
Lower Mobility ◽  
General Method

Manufacturing and assembly (geometric) errors affect the positioning precision of manipulators. In six degrees-of-freedom (6DOF) manipulators, geometric error effects can be compensated through suitable calibration procedures. This, in general, is not possible in lower-mobility manipulators. Thus, methods that evaluate such effects must be implemented at the design stage to determine both which workspace region is less affected by these errors and which dimensional tolerances must be assigned to match given positioning-precision requirements. In the literature, such evaluations are mainly tailored on particular architectures, and the proposed techniques are difficult to extend. Here, a general discussion on how to take into account geometric error effects is presented together with a general method to solve this design problem. The proposed method can be applied to any nonoverconstrained architecture. Eventually, as a case study, the method is applied to the analysis of the geometric error effects of the translational parallel manipulator (TPM) Triflex-II.

Aircraft Landing Gears—The Past, Present and Future

1986 ◽  
Vol 200 (2) ◽  
pp. 75-92 ◽  
Author(s):  
D W Young
Keyword(s):  
Landing Gear ◽  
Future Developments ◽  
The Past ◽  
Aircraft Landing ◽  
Functional Efficiency ◽  
Landing Gears

This paper discusses landing gear basic requirements with a review of historic and current equipment designs, and concludes by pointing to possible future developments to improve functional efficiency.

scholarly journals A Multi-Step CNN-Based Estimation of Aircraft Landing Gear Angles

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8440
Author(s):  
Fuyang Li ◽  
Zhiguo Wu ◽  
Jingyu Li ◽  
Zhitong Lai ◽  
Botong Zhao ◽  
...  
Keyword(s):  
Vector Field ◽  
Target Detection ◽  
Landing Gear ◽  
Estimation Methods ◽  
Depth Information ◽  
Aircraft Landing ◽  
Key Points ◽  
Aircraft Landing Gear ◽  
Landing Gears ◽  
Rgb Image

This paper presents a method for measuring aircraft landing gear angles based on a monocular camera and the CAD aircraft model. Condition monitoring of the aircraft landing gear is a prerequisite for the safe landing of the aircraft. Traditional manual observation has an intense subjectivity. In recent years, target detection models dependent on deep learning and pose estimation methods relying on a single RGB image have made significant progress. Based on these advanced algorithms, this paper proposes a method for measuring the actual angles of landing gears in two-dimensional images. A single RGB image of an aircraft is inputted to the target detection module to obtain the key points of landing gears. The vector field network votes the key points of the fuselage after extraction and scale normalization of the pixels inside the aircraft prediction box. Knowing the pixel position of the key points and the constraints on the aircraft, the angle between the landing gear and fuselage plane can be calculated even without depth information. The vector field loss function is improved based on the distance between pixels and key points, and synthetic datasets of aircraft with different angle landing gears are created to verify the validity of the proposed algorithm. The experimental results show that the mean error of the proposed algorithm for the landing gears is less than 5 degrees on the light-varying dataset.

Fatigue Analysis for the Aircraft Landing Gear Connecting Parts

2013 ◽  
Vol 300-301 ◽  
pp. 870-873
Author(s):  
Ji Yan Li ◽  
Zhi Bing Yang
Keyword(s):  
Fatigue Life ◽  
Engineering Application ◽  
Simulation Method ◽  
Fatigue Analysis ◽  
Test Methods ◽  
Landing Gear ◽  
Theoretical Research ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Landing Gears

Landing gear is the critical component for aircrafts’ flight safety. According to the statistics, the accidents caused by the structure of landing gears and other structures relating to landing gears probably account for more than two thirds of the structural accidents. Fatigue failure is a key failure mode when the landing gears under the condition of alternating loads. Therefore it is very meaningful to develop the research on the fatigue life of the landing gears. The traditional fatigue analysis based on the test methods has many disadvantages, such as high cost and long test cycle. So a numerical simulation method was used to analyze the structural fatigue. Then the stress distribution and the fatigue life of the landing gear connecting parts under specific working conditions were studied. It turned out that the local fatigue performance of the component needed to be improved. The results have a certain value in engineering application and theoretical research, especially in improving the design level and working reliability of the aircraft landing gear.

Control of processing at multi-tool two-support setup

2020 ◽  
pp. 67-73
Author(s):  
N.D. YUsubov ◽  
G.M. Abbasova
Keyword(s):  
Degrees Of Freedom ◽  
Factor Model ◽  
Angular Displacement ◽  
Factor Models ◽  
Technological System ◽  
Displacement Control ◽  
Model Accuracy ◽  
Six Degrees Of Freedom ◽  
Angular Displacements ◽  
And Control

The accuracy of two-tool machining on automatic lathes is analyzed. Full-factor models of distortions and scattering fields of the performed dimensions, taking into account the flexibility of the technological system on six degrees of freedom, i. e. angular displacements in the technological system, were used in the research. Possibilities of design and control of two-tool adjustment are considered. Keywords turning processing, cutting mode, two-tool setup, full-factor model, accuracy, angular displacement, control, calculation [email protected]

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