Tolerance Design and Robust Study for The Joint Clearances of Landing Gear Retraction Mechanisms

Joint clearances inevitably affect the kinematic accuracy and robustness of landing gear retraction mechanisms. However, the complexity and uncertainty of the clearances lead to difficulty in establishing mathematic models and analyzing effects. In the interest of assessing the clearance effects on the kinematic accuracy of landing gears, an integrated tolerance theory is proposed in this paper. In the theory proposed, Jacobian–Torsor model is combined with robust analysis to establish the kinematic accuracy model and predict the influences of clearances. The overall steps to apply the theory presented in practice are given. A typical landing gear retraction mechanism is chosen for the case study and the results show that the tendencies of clearances can be observed. Through the process of tolerance design, robust study, and tolerance redesign, the kinematic accuracy is significantly improved. The integrated tolerance theory proposed and the study conducted will provide designers new insights for the clearance analysis of landing gear mechanisms.

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Kinematic Accuracy Method of Mechanisms Based on Tolerance Theories

Mathematical Problems in Engineering ◽

10.1155/2020/5023092 ◽

2020 ◽

Vol 2020 ◽

pp. 1-18

Author(s):

Li Zhang ◽

Hong Nie ◽

Xiaohui Wei

Keyword(s):

Tolerance Analysis ◽

Functional Element ◽

Physical Models ◽

Small Displacement ◽

Tolerance Design ◽

Dimensional Chain ◽

Movement Accuracy ◽

Kinematic Accuracy ◽

Tolerance Model ◽

Joint Clearances

Traditional tolerance analysis is mostly restricted to static analysis. However, tolerances of different components also affect the movement accuracy in a mechanism. In this paper, the idea of kinematic tolerance analysis is advanced. In the interest of achieving movement precision considering tolerance, a kinematic Jacobian model is established on the basis of a traditional dimensional chain and an original Jacobian model. The tolerances of functional element (FE) pairs are expressed as small-displacement screws. In addition, joint clearances resulting from tolerance design also influence the kinematic accuracy, and they are modeled by FE pairs. Two examples are presented to illustrate the rationality and the validity of the kinematic tolerance model. The results of the two examples are shown, and the discussion is presented. A physical model of the 2D example is also built up in 3DCS software. Based on the discussion, a comparison between the statistical and physical models is carried out, and the merits and demerits of both are listed.

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Case Study for Enhanced Accident Tolerance Design Changes

10.2172/1168654 ◽

2014 ◽

Cited By ~ 1

Author(s):

Steven Prescott ◽

Curtis Smith ◽

Tony Koonce

Keyword(s):

Tolerance Design ◽

Design Changes

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Robust tolerance design for function generation mechanisms with joint clearances

Mechanism and Machine Theory ◽

10.1016/j.mechmachtheory.2010.04.003 ◽

2010 ◽

Vol 45 (9) ◽

pp. 1286-1297 ◽

Cited By ~ 47

Author(s):

Xianzhen Huang ◽

Yimin Zhang

Keyword(s):

Tolerance Design ◽

Function Generation ◽

Joint Clearances ◽

Generation Mechanisms

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Landing Gear System: An ASM-Based Solution for the ABZ Case Study

Communications in Computer and Information Science - ABZ 2014: The Landing Gear Case Study ◽

10.1007/978-3-319-07512-9_10 ◽

2014 ◽

pp. 142-147 ◽

Cited By ~ 5

Author(s):

Felix Kossak

Keyword(s):

Landing Gear ◽

Gear System

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ABZ 2014: The Landing Gear Case Study

10.1007/978-3-319-07512-9 ◽

2014 ◽

Cited By ~ 10

Keyword(s):

Landing Gear ◽

Gear Case

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Modeling and Analyzing Using ASMs: The Landing Gear System Case Study

Communications in Computer and Information Science - ABZ 2014: The Landing Gear Case Study ◽

10.1007/978-3-319-07512-9_3 ◽

2014 ◽

pp. 36-51 ◽

Cited By ~ 2

Author(s):

Paolo Arcaini ◽

Angelo Gargantini ◽

Elvinia Riccobene

Keyword(s):

Landing Gear ◽

Gear System

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On robust analysis of paycheck: case study

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun201159040371 ◽

2011 ◽

Vol 59 (4) ◽

pp. 371-378 ◽

Cited By ~ 1

Author(s):

Michal Uherek ◽

Milan Stehlík ◽

Luboš Střelec

Keyword(s):

Social Security ◽

Normal Distribution ◽

Statistical Tests ◽

Real Data ◽

Pension Funds ◽

Robust Analysis ◽

Pension Systems ◽

Tests For Normality

Many statistical tests are constructed to check the validity of normal distribution. Here we propose a case study on analysis of paycheck where we employ the RT class of tests for normality firstly introduced in Střelec, Stehlík (2008). In particular such a study can be of interest for pension funds theoreticians and practitioners, which study the transitions of pension systems from one social security state to the another one. Our study illustrates some possible distributional deviations of salary residuals on a real data.

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Stabilization System for UAV Landing on Rough Ground by Adaptive 3D Sensing and High-Speed Landing Gear Adjustment

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2021.p0108 ◽

2021 ◽

Vol 33 (1) ◽

pp. 108-118

Author(s):

Mikihiro Ikura ◽

◽

Leo Miyashita ◽

Masatoshi Ishikawa

Keyword(s):

Unmanned Aerial Vehicles ◽

High Speed ◽

Landing Gear ◽

Detailed Measurement ◽

Contact Points ◽

Measurement Results ◽

3D Sensing ◽

Landing Gears ◽

Spatio Temporal ◽

Measurement Area

This paper proposes a real-time landing gear control system based on adaptive and high-speed 3D sensing to enable the safe landing of unmanned aerial vehicles (UAVs) on rough ground. The proposed system controls the measurement area on the ground according to the position and attitude of the UAV and enables high-speed 3D sensing of the focused areas in which the landing gears are expected to contact the ground. Furthermore, the spatio-temporal resolution of the measurement can be improved by focusing a measurement area and the proposed system can recognize the detailed shape of the ground and the dynamics. These detailed measurement results are used to control the lengths of the landing gears at high speed, and it is ensured that all the landing gears contact the ground simultaneously to reduce the instability at touchdown. In the experiment setup, the proposed system realized high-speed sensing for heights of contact points of two landing gears at a rate of 100 Hz and almost simultaneous contact on ground within 36 ms.

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Tolerance Synthesis Method for an Industrial Crank-Rocker Application

22nd Biennial Mechanisms Conference: Mechanism Design and Synthesis ◽

10.1115/detc1992-0330 ◽

1992 ◽

Author(s):

Mark M. Benner ◽

Arthur G. Erdman

Keyword(s):

Synthesis Method ◽

Angular Acceleration ◽

Solution Space ◽

Performance Criteria ◽

Synthesis Process ◽

Lead Times ◽

Windshield Wiper ◽

System A ◽

Joint Clearances

Abstract An emphasis on reducing product development lead-times in the automotive industry has received much attention recently. The synthesis and design of windshield wiper drive mechanisms is no exception. This paper examines and develops the new concept of performance synthesis for crank-rocker linkages with two prescribed positions as applied to windshield wiper systems. Various performance criteria are evaluated with respect to the effect on the desired motion of the crank-rocker linkage by manufacturing tolerances, elastic deflections and joint clearances. Three performance criteria are mapped in the crank-rocker synthesis solution space to aid in the selection of solutions when considering the performance demands of the windshield wiper system. A case study is presented to demonstrate the effectiveness of the new performance synthesis concept which simultaneously considers position tolerance sensitivity, transmission angles and angular acceleration magnitudes in the synthesis process.

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