Extending FMCS Test for Flight Simulation

2011 ◽  
Vol 88-89 ◽  
pp. 72-76
Author(s):  
Zhao Hui Li ◽  
Gang Li

By means of a simulator we could expand the test research scope which could not be reached with flight tests, and recover and repeat some special domain of the test course, and make many kinds of experiments about FMCS properties, functions and with embedded failures by combining simulation tests with practical structure. The reliability and creditability of simulation results could be increased under real FMCS in conjunction with semi-entity simulation. Simulators combining a real FMCS with digital simulation have been used extensively for evaluating the large matrix of FMCS contents.

Author(s):  
G. A. Kfoury ◽  
N. G. Chalhoub ◽  
N. A. Henein ◽  
W. Bryzik

The original version of the (P–ω) method is a model-based approach developed for determining the instantaneous friction torque in internal combustion engines. This scheme requires measurements of the cylinder gas pressure, the engine load torque, the crankshaft angular displacement and its time derivatives. The effects of the higher order dynamics of the crank-slider mechanism on the measured angular motion of the crankshaft have caused the (P–ω) method to yield erroneous results, especially, at high engine speeds. To alleviate this problem, a nonlinear sliding mode observer has been developed herein to accurately estimate the rigid and flexible motions of the piston-assembly/connecting-rod/crankshaft mechanism of a single cylinder engine. The observer has been designed to yield a robust performance in the presence of disturbances and modeling imprecision. The digital simulation results, generated under transient conditions that represent a decrease in the engine speed, have illustrated the rapid convergence of the estimated state variables to the actual ones in the presence of both structured and unstructured uncertainties. Moreover, this study has proven that the use of the estimated rather than the measured angular displacement of the crankshaft and its time derivatives can significantly improve the accuracy of the (P–ω) method in determining the instantaneous engine friction torque. However, the effects of structural deformations of the crank-slider mechanism have rendered the original version of the (P–ω) method to be inapplicable at high engine speeds. This problem has been addressed herein by modifying the formulation of the (P–ω) method in order to account for the first two elastic modes of the crankshaft torsional vibration. The simulation results confirm the good performance of the modified (P–ω) method in determining the instantaneous friction torque at high engine speeds.


Author(s):  
S J Zan

The past decade has seen significant advancements in modelling and simulation of the dynamic interface. The goal of the initial work in this area was to reduce the costs associated with first-of-class flight trials, and to deal with the backlog of aircraft-ship combinations for which flight-clearance envelopes were minimal or non-existent. A decade ago, piloted simulation of the dynamic interface appeared to be the obvious way to overcome these deficiencies. Validated models of fixed-wing and rotorcraft were in existence, and work began to combine these models with prescribed weather/lighting conditions (wind, rain, snow, fog, night, etc.), ship visuals, and motion. It had been envisioned that through the use of high-fidelity flight simulation, a test pilot could rapidly and safely determine the flight envelope boundaries without resorting to, or at least minimizing, flight trials. During the past decade, significant advancements in simulation fidelity did transpire due to increased computational power, an improved understanding of airwakes, and enhanced simulation capabilities. The article describes some of the fundamental and applied research that contributed to the improved fidelity, much of it gained in a collaborative fashion. To date, modelling and simulation technologies have not advanced to the state where they can replace flight tests to derive flight-clearance envelopes, but they have approached the point where they can augment flight tests and serve in a training capacity. The accrual of a training benefit has recently emerged and is a significant, though unplanned, dividend from the efforts directed towards flight-envelope prediction. This article sets out to examine some of the strengths and deficiencies of the current capabilities, and provides a discussion of the way forward. Modelling and simulation of the dynamic interface are discussed in a broad context, wherein they are defined to include non-piloted, non-real-time activities. The article will provide a critical review of many of these efforts to date, focusing primarily on aerodynamic issues. The article also discusses the challenges which are present for rotary-wing operations, for both small and large ships. It compares the environment in both cases and how that impacts the simulation requirements.


2014 ◽  
Vol 988 ◽  
pp. 241-244
Author(s):  
Hu Zhu ◽  
Wen Wen Lin ◽  
Jin Lan Bai

The digital simulation method for NC incremental sectional forming is studied and the forming effect of NC incremental integral forming and sectional forming is analyzed through the digital simulation method in this paper. Digital simulation results show that the proposed simulation method for NC incremental sectional forming is reasonable and achievable. The difference of the forming quality between NC incremental sectional forming and integral forming is small. The sectional forming method has feasibility.


Author(s):  
Fabrizio Nicolosi ◽  
Agostino De Marco ◽  
Vito Sabetta ◽  
Pierluigi Della Vecchia

2011 ◽  
Vol 80-81 ◽  
pp. 841-844
Author(s):  
Ling Yu ◽  
Yan Chun Zhao ◽  
Chun Qiang Jia

In this paper the nonlinear model of zero open symmetrical cylinder controlled by four-way slide valve system was established base on power bond graph. The flexible simulation model was building up by the use of simulink toolbox in MATLAB. The model’s dynamic characteristics were stimulated. The simulation results showed the nonlinear model could reflect the dynamic characteristics of the valve controlled cylinder accurately. So it provided scientific basis for estimating the characteristics and correct using of the controlled cylinder system.


2013 ◽  
Vol 732-733 ◽  
pp. 1415-1419 ◽  
Author(s):  
Chun Lin Guo ◽  
Jian Ting Xu ◽  
Yang Zhao ◽  
Xiang Ning Xiao

According to the first project using SVC to mitigate SSO in China, this paper builds the system model based on real time digtal simulator,and gives an introduction to the sysem model. Under typical operation mode and fault conditions,the performance of SVC is fully validated,it also analysis and comparise the performance of SVC under different operation modes. Simulation results show that the SVC can mitigate the SSO phenomenon.


Author(s):  
D. Weiner ◽  
F. S. Aschner ◽  
J. Dayan

This paper discusses the digital nonlinear simulation of a twin-spool gas generator-free turbine power generating unit. The mathematical model derived is flexible and can be easily converted to suit any other gas turbine. Simulation results were verified by comparison to measured data. The model was applied to optimize a fuel control schedule by methods of Mathematical Programming, taking into account the constraints imposed by the protective control of the system.


2012 ◽  
Vol 187 ◽  
pp. 15-19
Author(s):  
Dao Cheng Xie ◽  
Zhong Wei Wang ◽  
Qing Hua Zeng

To solve the problem of ground simulation of aerocraft attitude in hardware-in-the-loop simulation (HILS), recurrence of aerocraft attitude is realized using dSPACE emulator and three-axis turn table. The hardware configuration and key technologies of control system are introduced. Construction and downloading of the dynamic model is done in dSPACE monitor computer, the model is calculated in dSPACE emulator. The communication between dSPACE and turn table is settled with serial-port of DS4201s card. The rotate motion of the inner middle and outer axis correspond to the three-channel motion of the aerocraft body. Simulation results indicate that dSPACE finish calculating complicated dynamic model, sending and receiving velocity data through serial-port is proper, bandwidth of turn table satisfies the need of simulation. Real rotating velocity of turn table is displayed using Controldesk tools, and fits well with the digital simulation data in pitching yawing and rolling directions, and the need for real-time attitude simulation in HILS is satisfied.


Author(s):  
Masato Ikegawa ◽  
Eiji Ishii ◽  
Nobuhiro Harada ◽  
Tsuneaki Takagishi

An ink-particle flight simulation method for industrial, continuous-type inkjet printers was developed to clarify the factors that influence the print distortion. Print distortion is produced by aerodynamic and electric interference between the ink-particles flying from the nozzle onto the print-target. The necessary functions to do this, such as the calculation of electrostatic force in the electric field between the electrodes, the Coulomb’s force from other charged ink-particles, and the drag force in the inkjet stream for many flying ink-particles were added to a Lagrangian method in the fluid dynamic analysis software that was used for the simulation. The trajectories of the ink-particles flying from this nozzle onto the print target and the air-flow caused by them were calculated simultaneously in the simulation. The simulation results for the velocities and trajectories of the flying ink-particles were compared with the experimental ones using a high-speed camera. These simulation results were in good agreement with the experimental ones, and this helps to clarify the factors that influence the print distortion.


Sign in / Sign up

Export Citation Format

Share Document