Airworthiness aspects of new technologies: Interaction between aircraft structural dynamics and control systems

1998 ◽  
Vol 212 (5) ◽  
pp. 309-317 ◽  
Author(s):  
M Hockenhull
Keyword(s):  
Control Systems ◽  
Structural Dynamics ◽  
Flight Control ◽  
Closed Loop ◽  
New Technologies ◽  
Loop Control ◽  
Transport Aircraft ◽  
Control Load ◽  
Dynamics And Control ◽  
And Control

The application of electrical flight control systems to civil transport aircraft has directed attention to the need for improved airworthiness regulation. In this paper, the scope and interpretation of a new FAR/JAR Part 25 regulation in preparation is discussed, applicable to aircraft that have closed-loop control systems for flight control, load alleviation or stability augmentation, and have the potential to interact with the aircraft's structural dynamics.

Dynamics and Control of Global Instabilities in Open-Flows: A Linearized Approach

2010 ◽  
Vol 63 (3) ◽  
Author(s):  
Denis Sipp ◽  
Olivier Marquet ◽  
Philippe Meliga ◽  
Alexandre Barbagallo
Keyword(s):  
Closed Loop ◽  
Selection Process ◽  
Open Loop ◽  
Base Flow ◽  
Closed Loop Control ◽  
Mean Flow ◽  
Loop Control ◽  
Dynamics And Control ◽  
Global Modes ◽  
And Control

This review article addresses the dynamics and control of low-frequency unsteadiness, as observed in some aerodynamic applications. It presents a coherent and rigorous linearized approach, which enables both to describe the dynamics of commonly encountered open-flows and to design open-loop and closed-loop control strategies, in view of suppressing or delaying instabilities. The approach is global in the sense that both cross-stream and streamwise directions are discretized in the evolution operator. New light will therefore be shed on the streamwise properties of open-flows. In the case of oscillator flows, the unsteadiness is due to the existence of unstable global modes, i.e., unstable eigenfunctions of the linearized Navier–Stokes operator. The influence of nonlinearities on the dynamics is studied by deriving nonlinear amplitude equations, which accurately describe the dynamics of the flow in the vicinity of the bifurcation threshold. These equations also enable us to analyze the mean flow induced by the nonlinearities as well as the stability properties of this flow. The open-loop control of unsteadiness is then studied by a sensitivity analysis of the eigenvalues with respect to base-flow modifications. With this approach, we manage to a priori identify regions of the flow where a small control cylinder suppresses unsteadiness. Then, a closed-loop control approach was implemented for the case of an unstable open-cavity flow. We have combined model reduction techniques and optimal control theory to stabilize the unstable eigenvalues. Various reduced-order-models based on global modes, proper orthogonal decomposition modes, and balanced modes were tested and evaluated according to their ability to reproduce the input-output behavior between the actuator and the sensor. Finally, we consider the case of noise-amplifiers, such as boundary-layer flows and jets, which are stable when viewed in a global framework. The importance of the singular value decomposition of the global resolvent will be highlighted in order to understand the frequency selection process in such flows.

Dynamics and control of gearshifts on twin-clutch transmissions

2005 ◽  
Vol 219 (8) ◽  
pp. 951-963 ◽  
Author(s):  
M Goetz ◽  
M C Levesley ◽  
D A Crolla
Keyword(s):  
Closed Loop ◽  
Closed Loop Control ◽  
Loop Control ◽  
Engine Torque ◽  
Shift Quality ◽  
Powertrain Control ◽  
Cone Type ◽  
Dynamics And Control ◽  
Automotive Powertrain ◽  
And Control

Based on a detailed dynamic model of an automotive powertrain containing a twin-clutch transmission, an integrated powertrain control for gearshifts is developed. The operation of this controller is demonstrated on the basis of simulation results for upshifts, downshifts, and multiple gearshifts taking place within the same half of the transmission. The control algorithm makes use of closed-loop control of clutch slip for a smooth transfer of engine torque with the aim of reproducing the operation of a one-way clutch. Further elements are a closed-loop control of engine speed through a combination of a manipulation of engine controls and clutch pressure. In addition, it is demonstrated that the control of transmission output torque during gearshifts can add robustness to the control and provides a means to manipulate directly the gearshift character. Finally, the dynamic effects of gear preselection through conventional hydraulically actuated cone-type synchronizers on the overall shift quality are discussed.

HYDRAULICS IN INDUSTRY

1960 ◽  
Vol 12 (5) ◽  
pp. 27-33
Author(s):  
FAREL BRADBURY
Keyword(s):  
Control Systems ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Hydraulic Power ◽  
Fluid Medium ◽  
Loop Control ◽  
Power And Control ◽  
And Control ◽  
Transmitting Element

HYDRAULIC POWER and control is being applied more and more widely in industry and is finding both general and specialised uses. Generally, hydraulics could be just another item in the designer's toolchest—another way of applying power and of exercising control. In the specialist fields hydraulics is being used as the force transmitting element in complex closed loop control systems and where the very nature of a fluid medium is to be used with advantage.

EEG-FES-Force-MMG closed-loop control systems of a volunteer with paraplegia considering motor imagery with fatigue recognition and automatic shut-off

2021 ◽  
Vol 68 ◽  
pp. 102662
Author(s):  
Paulo Broniera Junior ◽  
Daniel Prado Campos ◽  
André Eugenio Lazzaretti ◽  
Percy Nohama ◽  
Aparecido Augusto Carvalho ◽  
...  
Keyword(s):  
Control Systems ◽  
Motor Imagery ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Loop Control

A Control Strategy for Intelligent Stamp Forming Tooling

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
William J. Emblom ◽  
Klaus J. Weinmann
Keyword(s):  
Fuzzy Logic ◽  
Control Systems ◽  
Control Strategy ◽  
Pid Controller ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Linear Quadratic ◽  
Blank Holder ◽  
Loop Control ◽  
Stamp Forming

This paper describes the development and implementation of closed-loop control for oval stamp forming tooling using MATLAB®’s SIMULINK® and the dSPACE®CONTROLDESK®. A traditional PID controller was used for the blank holder pressure and an advanced controller utilizing fuzzy logic combining a linear quadratic gauss controller and a bang–bang controller was used to control draw bead position. The draw beads were used to control local forces near the draw beads. The blank holder pressures were used to control both wrinkling and local forces during forming. It was shown that a complex, advanced controller could be modeled using MATLAB’s SIMULINK and implemented in DSPACE CONTROLDESK. The resulting control systems for blank holder pressures and draw beads were used to control simultaneously local punch forces and wrinkling during the forming operation thereby resulting in a complex control strategy that could be used to improve the robustness of the stamp forming processes.

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