A Landing Gear Drop Dynamic Simulation Based on the LMS. Virtual. Lab

2011 ◽  
Vol 55-57 ◽  
pp. 684-687
Author(s):  
Li Zhang ◽  
Cai Jun Xue
Keyword(s):  
Influence Factors ◽  
Landing Gear ◽  
Buffer System ◽  
Air Spring ◽  
Damping Force ◽  
Tire Force ◽  
Virtual Lab ◽  
Spring Force ◽  
Simulation Based ◽  
Fluid Damping

In order to evaluate the dynamic behavior of the buffer of the Seagull 300 aircraft’s main landing gear, a drop model is built to simulate the drop dynamics using the software of LMS Virtual Lab Motion. The fluid damping force of the buffer, the air spring force of the buffer, the tire force of the landing gear and the weight of the fuselage are considered in the model. The simulation results are compared with the results of the Seagull 300 landing gears drop test, which proves the accuracy of the simulation model. Then the buffer performance and its influence factors are computationally discussed. This method gives a new way to study and improve the performance of the buffer system of an aircraft.

Aircraft Landing Gear of a Dynamic Research and Computer Simulation

2011 ◽  
Vol 383-390 ◽  
pp. 2426-2429 ◽  
Author(s):  
Shen Shou Li ◽  
Xiao Ming Liu ◽  
Zhong Gan Zhu ◽  
Fang Yang
Keyword(s):  
Landing Gear ◽  
Structural Constraints ◽  
Test Results ◽  
Dynamics Model ◽  
Damping Force ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Spring Force ◽  
Adams Software ◽  
Software Modules

by the MSC Adams / Aircraft software features, setting pillar-type landing gear as the prototype, and using ADAMS software modules prior to the establishment of a certain type of aircraft landing gear model, then calculate the air buffer spring force oil, damping force and the structural constraints force curve based on dynamics model, At the end of paper we will analyze the model drop-test results. The results proved that we used this method was feasible.

scholarly journals Robust force and displacement control of an active landing gear for vibration reduction at touchdown and during taxiing

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Mehran Pirooz ◽  
Seyed Hossein Mirmahdi ◽  
Ahmad Reza Khoogar
Keyword(s):  
Control System ◽  
Force Control ◽  
Direct Method ◽  
Landing Gear ◽  
Gear System ◽  
Displacement Control ◽  
Robust Nonlinear Control ◽  
Control Loops ◽  
Tire Force ◽  
The Mathematical Model

AbstractIn this paper, a new approach is proposed to control the dynamic response of a landing gear system subjected to runway force, both on heavy landing conditions and at the taxiing process. The mathematical model of the system is used in a way that covers nonlinear dynamics characteristics of landing gear and nonlinear/nonaffine property of the external actuator. The operation of the landing gear system and its components are described briefly. The desired control system includes two different interior loops for displacement and force control. The inner loop determines the actuator force and the outer loop performs the displacement control. A lumped uncertainty is considered in both displacement and force control loops that represent uncertainties including parametric errors, measurement noises, unmodeled dynamics, disturbance due to runway excitation, and other disturbances. The direct method of Lyapunov is utilized for asymptotic stability analysis of the robust nonlinear control system (RNCS). This system is simulated in MATLAB software and the performance of the proposed controller is analyzed exactly. Besides, the results are compared with a passive system and conventional PID control. The comparison indicates that RNCS works better and more precisely. This method can reduce vibrations at touchdown and taxiing and effectively overcome uncertainty and provide well aircraft handling by decreasing the changes in tire force.

Comparison of Stopping Modes for Pod-Driven Ships by Simulation Based on Model Testing

2005 ◽  
Vol 219 (2) ◽  
pp. 47-64 ◽  
Author(s):  
M D Woodward ◽  
M Atlar ◽  
D Clarke
Keyword(s):  
Load Condition ◽  
Open Water ◽  
Water Model ◽  
Simulation Algorithm ◽  
Time Domain Simulation ◽  
Dynamic Effects ◽  
Study Results ◽  
Simulation Based ◽  
Fluid Damping

Conventionally, the stopping of a ship is achieved by direct reversal of propeller rotation. However, the introduction of azimuthing pods presents other options. The following study examines the various modes that may be employed to stop a pod-driven ship. A continuous function is derived describing the hydrodynamic forces on both the propeller and the pod body for any load condition and helm angle, including fluid damping and added mass effects. The proposed function is validated through comparison with comprehensive open water model tests. Next, a time domain simulation algorithm is proposed to examine the dynamic effects including the mass inertia on both the propeller shaft and slewing stock. Finally, a simulation study for the proposed stopping modes is performed using a known design as a case study. Results and discussion are presented.

EASY5 Model of Two Position Solenoid Operated Cartridge Valve

2002 ◽  
Author(s):  
Song Liu ◽  
Gary Krutz ◽  
Bin Yao
Keyword(s):  
Control Valve ◽  
Mathematic Model ◽  
Nonlinear Flow ◽  
Damping Force ◽  
Precise Control ◽  
Directional Control ◽  
Spring Force ◽  
Programmable Valve ◽  
Valve Dynamics ◽  
Nonlinear Performance

The two position solenoid operated cartridge valve is widely used in the applications, such as process control systems, pavers, agricultural machinery, where response and installed costs are more important than precise control through electronic position feedback. In recent years, the combination of multiple cartridge valves, so called ‘smart valve’ or ‘programmable valve’, which is able to break the mechanical linkage between the meter-in and meter-out orifices and enables high precision control as well as optimal usage of energy, is gaining engineering interests. But the control of such combination is far from trivial. It demands good knowledge of the valve dynamics and nonlinear flow properties. Unlike servo valve or proportional directional control valve, a mathematic model of solenoid operated cartridge valve, or even a thorough understanding of the dynamics and nonlinear performance, are not available. This paper presents an EASY 5 model for the two position solenoid operated cartridge valve. The model, which includes the solenoid force, spring force, damping force, flow force and nonlinear mass flow rate, can be used to analyze cartridge valve as well as simulate system or controller performance. It is also able to connect with Matlab for more complicated simulation.

scholarly journals Design and Simulation of Electromagnetic Linear Actuators for Jet Dispensers

2020 ◽  
Vol 10 (5) ◽  
pp. 1653
Author(s):  
Minh-Sang Tran ◽  
Sheng-Jye Hwang
Keyword(s):  
Thrust Force ◽  
Inertia Force ◽  
Resistance Force ◽  
Driving Frequency ◽  
Excitation Current ◽  
Damping Force ◽  
Element Analysis ◽  
Spring Force ◽  
Return Spring ◽  
Linear Actuators

Three electromagnetic-based linear actuators, namely a solenoid actuator (SA), a moving coil actuator (MCA), and a moving magnet actuator (MMA), are proposed for driving the needle in a jet dispenser. The total resistance force acting on the needle during operation, including the damping force, the friction force, the inertia force, the compression spring force, and the backpressure, are measured by an experimental model. The thrust force required to overcome this resistance force is then predicted for each actuator using finite element analysis (FEA) simulations. Simple two-dimensional models of the SA, MCA, and MMA are constructed using the same coil dimensions in every case in order to facilitate an objective comparison between them. Simulations in ANSYS Maxwell software are then performed to adjust the specific dimensions of each actuator structure in such a way as to generate the thrust force required to drive the needle in the jet dispenser with the minimum excitation current possible. The simulation results show that for a maximum needle driving frequency of 250 Hz and a stroke length of 0.5 mm, the excitation current required to generate the necessary thrust force is equal to 1.8 A and 1.9 A for the MCA and MMA models, respectively, when a return spring is not used, and 2.2 A, 3.8 A, and 4.1 A for the SA, MCA, and MMA models, respectively, when a return spring is employed. It is additionally shown that the thrust force drop of the MCA and MMA models is far less than that of the SA model, about 0.7%, 1.8%, and 61% for three models, respectively. Three preliminary designs for jet dispensers incorporating the proposed actuators are also generated for reference purposes.

Performance Enhancement of a Friction Damper System Using Bond Graphs

Volume 1 ◽  
2004 ◽  
Author(s):  
Roger F. Ngwompo ◽  
Emanuele Guglielmino ◽  
Kevin A. Edge
Keyword(s):  
Control System ◽  
Performance Enhancement ◽  
Pressure Control ◽  
Back Pressure ◽  
Friction Damper ◽  
Bond Graphs ◽  
Damping Force ◽  
Actual System ◽  
Local Pressure ◽  
Spring Force

This paper describes a study of the performance of a servo-driven dry-friction damper employed in a vehicle suspension application. The damper is force-controlled via an electrohydraulic pressure control system. Previous experimental work showed that the theoretically predicted system performance does not reflect actual system behaviour because of both the residual back-pressure which produces an undesired constant-amplitude damping force and reduced hydraulic system bandwidth due to presence of free air within the hydraulic fluid. Possible solutions are proposed and performance assessed against a simulated system with dynamic performance purposely worsened. The first issue can be addressed by spring-preloading the friction damper so as to compensate the constant force caused by the residual back-pressure. The second issue can be tackled by closing a local pressure control loop around the control valve. The friction damper is controlled by a variable structure scheme that performs spring force compensation tracking. Bond graphs are employed as a tool for modelling and designing the control system.

Vibration Suppression Performance of a Desktop Vibration Isolator Supported by Four Air Spring

2017 ◽  
Author(s):  
Yuichi Baba ◽  
Kento Onishi ◽  
Toshihiko Asami
Keyword(s):  
Support System ◽  
Vibration Isolation ◽  
Vibration Suppression ◽  
Theoretical Calculations ◽  
Small Diameter ◽  
Measuring Instruments ◽  
Vibration Isolator ◽  
Air Spring ◽  
Damping Force ◽  
Vibration Isolators

Desktop vibration isolators are often used as precision measuring instruments. This article discusses the accuracy of performance prediction methods for vibration isolators elastically supported by four air springs. Each air spring possesses a reservoir tank to ensure the natural frequency of the support system remains low and to provide adequate damping force. For practical use, air springs and reservoir tanks should be installed in separate locations and connected by a small-diameter pipe because desktop isolators must be thin. Our previous studies have shown that there is a secondary resonance point in systems supported by air springs with long pipes and reservoir tanks and that it is not simple to theoretically calculate the amplitude and frequency at this point because this type of air spring support system has nonlinear characteristics. In this study, the change in the vibration isolation performance of a desktop vibration isolator with the length of the pipe connecting the main air tank and the reservoir tank of an air spring-supported system was examined experimentally and approximated using theoretical calculations.

Simulation and Test of ASAC Dynamic Characteristic Based on ABAQUS

2013 ◽  
Vol 765-767 ◽  
pp. 331-335 ◽  
Author(s):  
Li Qin Sun ◽  
Zhong Xing Li ◽  
Xu Feng Shen ◽  
Ji Wei Guo
Keyword(s):  
Finite Element ◽  
Geometric Nonlinearity ◽  
Influence Factors ◽  
Initial Pressure ◽  
Element Model ◽  
Nonlinear Characteristic ◽  
Static Stiffness ◽  
Air Spring ◽  
Good Consistency ◽  
Simulation Results

Considering the influence factors of material nonlinearity ,geometric nonlinearity and etc.of air spring with auxiliary chamber in numerical calculations, implement method of airbag nonlinear characteristic ,gas unit, connecting pipe were defined. Finite element model was established in ABAQUS,and vertical characteristic simulation was carried out ,and the results shows that, system static stiffness reduces when increasing in the volume of the auxiliary chamber, but the change in stiffness is not is obvious when the volume increases to a certain degree, and static stiffness also reduces when initial pressure reducing. Simulation results are verified through characteristic test,and both are in good consistency.

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