Adaptive Control of a High Agility Model Airplane in the Presence of Severe Structural Damage and Failures

2011 ◽  
pp. 201-211 ◽  
Author(s):  
Stephan Baur ◽  
Travis Gibson ◽  
Anuradha Annaswamy ◽  
Leonhard Höcht ◽  
Thomas Bierling ◽  
...  
Keyword(s):  
Adaptive Control ◽  
Structural Damage

Direct adaptive algorithm for seismic control of damaged structures with faulty sensors

2017 ◽  
Vol 24 (24) ◽  
pp. 5854-5866 ◽  
Author(s):  
Amin Hosseini ◽  
Touraj Taghikhany ◽  
Arash Yeganeh Fallah
Keyword(s):  
Adaptive Control ◽  
Seismic Response ◽  
Structural Damage ◽  
Control Method ◽  
Control Strategies ◽  
Magnetorheological Damper ◽  
Main Concern ◽  
Building Structures ◽  
Steel Moment Resisting Frames ◽  
Seismic Control

In recent decades, the application of semi-active control strategies has gained much attention as a way to reduce the seismic response of civil infrastructures. However, uncertainty in the modeling process of systems with possible partial or total failure during an earthquake is the main concern of engineers about the reliability of this strategy. In this regard, adaptive control algorithms are known as an effective solution to adjust control parameters with different uncertainties. In the current study, the efficiency of the simple adaptive control method (SACM) is investigated to control the seismic response of building structures in the presence of unknown structural damage and fault in the sensors. The method is evaluated in 20-story steel moment resisting frames with different arrangement of smart dampers and sensors with various damage and fault scenarios. The results show that the SACM control system can effectively reduce the maximum inter-story drift of the structure in all different assumed magnetorheological damper arrangements. Furthermore, combination of a Kalman–Bucy filter with the SACM improves robustness of the controller to the uncertainties of sensors faults and damages of structural elements.

Nonlinear robust adaptive control of an airplane with structural damage

2020 ◽  
Vol 234 (14) ◽  
pp. 2076-2088
Author(s):  
Davood Asadi ◽  
Karim Ahmadi
Keyword(s):  
Adaptive Control ◽  
Structural Damage ◽  
Control Algorithm ◽  
Transport Model ◽  
Sliding Mode ◽  
Robust Adaptive Control ◽  
Damage Effect ◽  
Wing Damage ◽  
Robust Adaptive ◽  
Nonlinear Robust

This article investigates the design of a novel nonlinear robust adaptive control architecture to stabilize and control an airplane in the presence of left-wing damage. Damage effect is modeled by considering the sudden mass and inertia changes, center of gravity, and aerodynamic variations. The novel nonlinear control algorithm applies a state predictor as well as the error between the real damaged dynamics and a virtual model based on the nominal aircraft dynamics in the control loop of the adaptive strategy. The projection operator is used for the purpose of robustness of the adaptive control algorithm. The stability of the proposed nonlinear robust adaptive controller is demonstrated applying the Lyapunov stability theory. The performance of the proposed controller is compared with two previous successful algorithms, which are implemented on the Generic Transport Model airplane to accommodate wing damage. Numerical simulations demonstrate the effectiveness and advantages of the proposed robust adaptive algorithm regarding two other algorithms of adaptive sliding mode and L 1 adaptive control.

Nonlinear L1 adaptive control of an airplane with structural damage

2017 ◽  
Vol 233 (1) ◽  
pp. 341-353 ◽  
Author(s):  
Karim Ahmadi ◽  
Davood Asadi ◽  
Farshad Pazooki
Keyword(s):  
Adaptive Control ◽  
Control Strategy ◽  
Nonlinear Dynamic ◽  
Structural Damage ◽  
Adaptive Controller ◽  
Model Reference Adaptive Control ◽  
Dynamic Inversion ◽  
Model Reference ◽  
Model Reference Adaptive ◽  
Nonlinear Dynamic Inversion

This paper investigates the design of a novel nonlinear L1 adaptive control architecture to stabilize and control an aircraft with structural damage. The airplane nonlinear model is developed considering center of gravity variation and aerodynamic changes due to damage. The new control strategy is applied by using nonlinear dynamic inversion as a baseline augmented with an L1 adaptive control strategy on NASA generic transport model in presence of un-modeled actuator dynamics, wing and vertical tail damage. The L1 adaptive controller with appropriate design of filter and gains is applied to accommodate uncertainty due to structural damage and un-modeled dynamics in the nonlinear dynamic inversion loop, and to meet desired performance requirements. The properties of the proposed nonlinear adaptive controller are investigated against a model reference adaptive control, a robust model reference adaptive control, and an adaptive sliding mode control strategy. The results clearly represent the excellent overall performance of the designed controller.

Adaptive Actuator Failure and Structural Damage Compensation of NASA Generic Transport Model

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Jiaxing Guo ◽  
Gang Tao ◽  
Yu Liu
Keyword(s):  
Adaptive Control ◽  
Structural Damage ◽  
Transport Model ◽  
Fault Tolerant ◽  
Model Reference Adaptive Control ◽  
Multivariable Model ◽  
Model Reference ◽  
Actuator Failures ◽  
Aircraft Systems ◽  
Model Reference Adaptive

This paper studies design and evaluation of a multivariable model reference adaptive control (MRAC) scheme for aircraft systems under simultaneous actuator failures and structural damage. A key design condition–system infinite zero structure is investigated for nominal and posthazard aircraft systems and the invariance of this essential condition is concluded under realistic failure and damage conditions. The multivariable model reference adaptive control scheme is developed to ensure stability and asymptotic output tracking for the aircraft in the presence of uncertain actuator failures and structural damage. The developed fault-tolerant control design is evaluated by a high-fidelity nonlinear aircraft model–the NASA generic transport model.

Evaluation of single-electron movies of glutamine synthetase molecules

1983 ◽  
Vol 41 ◽  
pp. 280-281
Author(s):  
W. Kunath ◽  
E. Zeitler ◽  
M. Kessel
Keyword(s):  
Electron Microscope ◽  
Glutamine Synthetase ◽  
Electron Irradiation ◽  
Structural Damage ◽  
Structural Changes ◽  
Single Electron ◽  
Continuous Series ◽  
Digital Recording ◽  
Recording Device ◽  
Low Exposure

The features of digital recording of a continuous series (movie) of singleelectron TV frames are reported. The technique is used to investigate structural changes in negatively stained glutamine synthetase molecules (GS) during electron irradiation and, as an ultimate goal, to look for the molecules' “undamaged” structure, say, after a 1 e/Å2 dose.The TV frame of fig. la shows an image of 5 glutamine synthetase molecules exposed to 1/150 e/Å2. Every single electron is recorded as a unit signal in a 256 ×256 field. The extremely low exposure of a single TV frame as dictated by the single-electron recording device including the electron microscope requires accumulation of 150 TV frames into one frame (fig. lb) thus achieving a reasonable compromise between the conflicting aspects of exposure time per frame of 3 sec. vs. object drift of less than 1 Å, and exposure per frame of 1 e/Å2 vs. rate of structural damage.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

Modification of the Electron Microscope for Investigation of Fully Hydrated Biological Specimens

1969 ◽  
Vol 27 ◽  
pp. 418-419 ◽  
Author(s):  
R. C. Moretz ◽  
D. F. Parsons
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Structural Damage ◽  
Lower Percentage ◽  
Vacuum Drying ◽  
Total Removal ◽  
Total Absence ◽  
Biological Studies ◽  
Electron Microscopes ◽  
Beam Damage

Short lifetime or total absence of electron diffraction of ordered biological specimens is an indication that the specimen undergoes extensive molecular structural damage in the electron microscope. The specimen damage is due to the interaction of the electron beam (40-100 kV) with the specimen and the total removal of water from the structure by vacuum drying. The lower percentage of inelastic scattering at 1 MeV makes it possible to minimize the beam damage to the specimen. The elimination of vacuum drying by modification of the electron microscope is expected to allow more meaningful investigations of biological specimens at 100 kV until 1 MeV electron microscopes become more readily available. One modification, two-film microchambers, has been explored for both biological and non-biological studies.

Slow-scan CCD cameras and low-dose High-Resolution Electron Microscopy: Direct and quantitative

1994 ◽  
Vol 52 ◽  
pp. 412-413
Author(s):  
M. Pan
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Structural Damage ◽  
Low Dose ◽  
Dynamic Range ◽  
High Resolution Electron Microscopy ◽  
Operating Conditions ◽  
Digital Data ◽  
Ccd Cameras ◽  
Resolution Electron

It has been known for many years that materials such as zeolites, polymers, and biological specimens have crystalline structures that are vulnerable to electron beam irradiation. This radiation damage severely restrains the use of high resolution electron microscopy (HREM). As a result, structural characterization of these materials using HREM techniques becomes difficult and challenging. The emergence of slow-scan CCD cameras in recent years has made it possible to record high resolution (∽2Å) structural images with low beam intensity before any apparent structural damage occurs. Among the many ideal properties of slow-scan CCD cameras, the low readout noise and digital recording allow for low-dose HREM to be carried out in an efficient and quantitative way. For example, the image quality (or resolution) can be readily evaluated on-line at the microscope and this information can then be used to optimize the operating conditions, thus ensuring that high quality images are recorded. Since slow-scan CCD cameras output (undistorted) digital data within the large dynamic range (103-104), they are ideal for quantitative electron diffraction and microscopy.

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