Active control of transonic buffet flow

2017 ◽  
Vol 824 ◽  
pp. 312-351 ◽  
Author(s):  
Chuanqiang Gao ◽  
Weiwei Zhang ◽  
Jiaqing Kou ◽  
Yilang Liu ◽  
Zhengyin Ye
Keyword(s):  
Feedback Control ◽  
Design Flow ◽  
Complex Conjugate ◽  
Control Input ◽  
Input Output ◽  
Linear Quadratic ◽  
Unstable Flow ◽  
Control Laws ◽  
Loop Control ◽  
Transonic Buffet

Transonic buffet is a phenomenon of aerodynamic instability with shock wave motions which occurs at certain combinations of Mach number and mean angle of attack, and which limits the aircraft flight envelope. The objective of this study is to develop a modelling method for unstable flow with oscillating shock waves and moving boundaries, and to perform model-based feedback control of the two-dimensional buffet flow by means of trailing-edge flap oscillations. System identification based on the ARX algorithm is first used to derive a linear model of the input–output dynamics between the flap rotation (the control input) and the lift and pitching moment coefficients (system outputs). The model features a pair of unstable complex-conjugate poles at the characteristic buffet frequency. An appropriate reduced-order model (ROM) with a lower dimension is further obtained by a balanced truncation method that keeps the pair of unstable poles in the unstable subspace but truncates the dynamics in the stable subspace. Based on this balanced ROM, two kinds of feedback control are designed by pole assignment and linear quadratic methods respectively. These independent designs, however, result in similar suboptimal static output feedback control laws. When introduced in numerical simulations, they are both able to completely suppress the buffet instability. Furthermore, the resulting controllers are even able to stabilize buffet flows with nonlinear disturbances and in off-design flow conditions, thus implying their robustness. The analysis of the feedback control laws indicates that parameters (frequency and phase) corresponding to the ‘anti-resonance’ of the linear input–output model are vital for optimal control. The best performance is obtained when the control operates close to the ‘anti-resonance’, which is supported by the optimal frequency and the phase of the open-loop control as well as by the optimal phase of the closed-loop control.

Linear Closed-Loop Control of Fluid Instabilities and Noise-Induced Perturbations: A Review of Approaches and Tools1

2016 ◽  
Vol 68 (2) ◽  
Author(s):  
Denis Sipp ◽  
Peter J. Schmid
Keyword(s):  
Large Scale ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Control Input ◽  
Input Output ◽  
Control Laws ◽  
Loop Control ◽  
Stability Robustness ◽  
Data Control ◽  
Galerkin Models

This review article is concerned with the design of linear reduced-order models and control laws for closed-loop control of instabilities in transitional flows. For oscillator flows, such as open-cavity flows, we suggest the use of optimal control techniques with Galerkin models based on unstable global modes and balanced modes. Particular attention has to be paid to stability–robustness properties of the control law. Specifically, we show that large delays and strong amplification between the control input and the estimation sensor may be detrimental both to performance and robustness. For amplifier flows, such as backward-facing step flow, the requirement to account for the upstream disturbance environment rules out Galerkin models. In this case, an upstream sensor is introduced to detect incoming perturbations, and identification methods are used to fit a model structure to available input–output data. Control laws, obtained by direct inversion of the input–output relations, are found to be robust when applied to the large-scale numerical simulation. All the concepts are presented in a step-by-step manner, and numerical codes are provided for the interested reader.

Modeling and Control of a Rotary Crane

1985 ◽  
Vol 107 (3) ◽  
pp. 200-206 ◽  
Author(s):  
Y. Sakawa ◽  
A. Nakazumi
Keyword(s):  
Feedback Control ◽  
Equilibrium State ◽  
Open Loop ◽  
The State ◽  
Control Input ◽  
Loop Control ◽  
Modeling And Control ◽  
Control Scheme ◽  
Rotary Crane ◽  
And Control

In this paper we first derive a dynamical model for the control of a rotary crane, which makes three kinds of motion (rotation, load hoisting, and boom hoisting) simultaneously. The goal is to transfer a load to a desired place in such a way that at the end of transfer the swing of the load decays as quickly as possible. We first apply an open-loop control input to the system such that the state of the system can be transferred to a neighborhood of the equilibrium state. Then we apply a feedback control signal so that the state of the system approaches the equilibrium state as quickly as possible. The results of computer simulation prove that the open-loop plus feedback control scheme works well.

Payload Pendulation Reduction Using a Variable-Geometry-Truss Architecture with LQR and Fuzzy Controls

2003 ◽  
Vol 9 (7) ◽  
pp. 805-837 ◽  
Author(s):  
Paolo Dadone ◽  
Walter Lacarbonara ◽  
Ali H. Nayfeh ◽  
Hugh F. Vanlandingham
Keyword(s):  
Control Point ◽  
Broad Band ◽  
Ship Motions ◽  
Control Input ◽  
Variable Geometry ◽  
Linear Quadratic ◽  
Control Laws ◽  
Band Frequency ◽  
Input Acceleration ◽  
Variable Geometry Truss

We investigate the feasibility of a variable-geometry truss (VGT) based architecture for suppressing payload pendulations in ship-mounted cranes. The VGT assembly is conceived to be retrofitted onto the boom tip of ship-mounted cranes. A simplified planar model is developed. A control point along the cable hoisting the payload is constrained to move along a straight path with a given control input (acceleration) imparted via the actuators embedded in the VGT assembly. Control laws based on either linear quadratic or fuzzy control methodologies are developed in order to minimize an assigned cost functional. Their effectiveness is compared through extensive numerical simulations. The performance of the VGT architecture and associated control laws is analyzed when the crane is subject to the most severe combination of resonant excitations: a primary resonant roll excitation at the natural frequency of the controlled system, and a principal-parametric resonant heave excitation, both corresponding to sea state three and higher. The proposed strategy exhibits enough control authority over the system dynamics, greatly reducing the severe and undesirable resonant pendulations caused by the ship motions in a broad-band frequency range. Moreover, its disturbance-rejection capabilities are exerted with feasible control efforts, which are localized in the segment of the crane where they are needed.

On Passive Implementation of Feedback Control Systems

1989 ◽  
Vol 111 (2) ◽  
pp. 339-342
Author(s):  
R. Shoureshi
Keyword(s):  
Feedback Control ◽  
Control Systems ◽  
State Feedback ◽  
Closed Loop ◽  
State Feedback Control ◽  
Closed Loop Control ◽  
Linear Quadratic ◽  
Loop Control ◽  
Feedback Control Systems ◽  
Linear Quadratic Regulators

Closed-loop control systems, especially linear quadratic regulators (LQR), require feedbacks of all states. This requirement may not be feasible for those systems which have limitations due to geometry, power, required sensors, size, and cost. To overcome such requirements a passive method for implementation of state feedback control systems is presented.

Theoretical and experimental investigations on an active control system for vertical fin buffeting alleviation using strain actuation

2001 ◽  
Vol 105 (1047) ◽  
pp. 277-285 ◽  
Author(s):  
F. Nitzsche ◽  
S. Liberatore ◽  
D. G. Zimcik
Keyword(s):  
Control System ◽  
Ground Vibration ◽  
Experimental Investigations ◽  
Linear Quadratic ◽  
Control Laws ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System ◽  
Vibration Tests ◽  
Time Invariant

Abstract In the present investigation, the results obtained during the ground vibration tests of a closed-loop control system conducted on a full-scale fighter to attenuate vertical fin buffeting response using strain actuation are presented. The experimental results are supported by numerical analyses using a finite element aeroelastic model of the structure. Two groups of actuators consisting of piezoelectric elements distributed over the structure were designed to achieve authority over the first and second modes of the vertical fin. The control laws were synthesised using the linear quadratic Gaussian (LQG) method for a time-invariant two-input, two-output (2x2 MIMO) control system. Three different pairs of sensors including strain gauges and accelerometers at different locations were used to close the feedback loop. The results demonstrated that actual reductions of up to 18% in the root-mean-square (RMS) values of the fin dynamic response measured by the strain transducer at the critical point for fatigue at the root were achieved for the second mode under the most severe buffet condition.

Formation Control of Under-Actuated Robotic Boats

2005 ◽  
Author(s):  
Farbod Fahimi ◽  
S. V. Sudhil Rineesh ◽  
C. Nataraj
Keyword(s):  
Feedback Control ◽  
Dynamic Model ◽  
Computer Simulations ◽  
Formation Control ◽  
Control Method ◽  
Degree Of Freedom ◽  
Input Output ◽  
Internal Dynamics ◽  
Control Laws ◽  
Three Degree Of Freedom

Feedback control laws for controlling multiple robotic boats in arbitrary formations are proposed. The presented formation control method uses only local sensor-based information. The method of input-output linearization has been used to exponentially stabilize the relative distance and orientation of neighboring boats with a three-degree-of-freedom dynamic model. It is shown that the internal dynamics of the system is also stable. The use of these control laws is demonstrated by computer simulations. These controllers can be utilized to control an arbitrarily large number of robotic boats moving in very general formations.

Discrete-Time Control of Linear Time-Periodic Systems

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
S. Kalender ◽  
H. Flashner
Keyword(s):  
Feedback Control ◽  
Discrete Time ◽  
Linear Time ◽  
Output Feedback Control ◽  
Control Design ◽  
Control Input ◽  
Control Laws ◽  
Point Mapping ◽  
Time Control ◽  
Time Varying Systems

A discrete-time control design approach for periodically time-varying systems is introduced. The method employs a period-to-period (point-mapping) formulation of the system’s dynamics and a parametrization of the control input to obtain an equivalent time-invariant discrete-time representation of the system. The representation is generalized to include sampling within the period and varying sampling rates in different feedback loops. The proposed formulation allows for the design of feedback control laws using established discrete-time control methodologies. In this paper, dead-beat and optimal control laws with state- or output-feedback control are presented. An example of a multivariable control design for double inverted pendulum with periodic forcing is used to illustrate the proposed approach.

Design of Finite Time Settling Regulators for Linear Systems

1994 ◽  
Vol 116 (4) ◽  
pp. 602-609 ◽  
Author(s):  
Slim Choura
Keyword(s):  
Finite Time ◽  
Feedforward Control ◽  
Linear Quadratic Regulator ◽  
Control Law ◽  
Control Input ◽  
Linear Quadratic ◽  
Control Laws ◽  
Performance Specifications ◽  
The Time Domain ◽  
State Responses

Earlier development of finite time settling controllers focused on the structure of the control law which consists of feedback and feedforward parts. In this structure, the feedback part is designed separately to satisfy certain performance specifications in the frequency and/or the time domain. The feedforward part is determined from the feedback control law, and therefore, there exists one-way coupling of both parts. In this paper, we propose a modification in the control structure that enables the designer to regulate the bounds of the control input and the state responses. We show that the finite time settling control problem can be transformed into a linear quadratic regulator one. This transformation results in a two-way coupling of the feedback and the feedforward control laws. We verify that the robustness property of the control strategy is preserved despite its structural change. In addition, we give guidelines for the selection of the feedforward control law.

scholarly journals Real-Time Energy Management of Parallel Hybrid Electric Vehicles Using Linear Quadratic Regulation

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5538
Author(s):  
Bảo-Huy Nguyễn ◽  
João Pedro F. Trovão ◽  
Ronan German ◽  
Alain Bouscayrol
Keyword(s):  
Real Time ◽  
Energy Management ◽  
Electric Vehicles ◽  
Hybrid Electric Vehicles ◽  
Engine Fuel ◽  
Linear Quadratic ◽  
Loop Control ◽  
Parallel Hybrid ◽  
Linear Quadratic Regulation ◽  
Hybrid Electric

Optimization-based methods are of interest for developing energy management strategies due to their high performance for hybrid electric vehicles. However, these methods are often complicated and may require strong computational efforts, which can prevent them from real-world applications. This paper proposes a novel real-time optimization-based torque distribution strategy for a parallel hybrid truck. The strategy aims to minimize the engine fuel consumption while ensuring battery charge-sustaining by using linear quadratic regulation in a closed-loop control scheme. Furthermore, by reformulating the problem, the obtained strategy does not require the information of the engine efficiency map like the previous works in literature. The obtained strategy is simple, straightforward, and therefore easy to be implemented in real-time platforms. The proposed method is evaluated via simulation by comparison to dynamic programming as a benchmark. Furthermore, the real-time ability of the proposed strategy is experimentally validated by using power hardware-in-the-loop simulation.

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