Robust augmented lateral acceleration flight control design for a quasi-linear parameter-varying missile

2005 ◽  
Vol 219 (2) ◽  
pp. 171-181 ◽  
Author(s):  
L Bruyere ◽  
A Tsourdos ◽  
B A White
Keyword(s):  
Linear Model ◽  
Closed Loop ◽  
Loop System ◽  
Lateral Acceleration ◽  
Linear Parameter ◽  
Input Output ◽  
Closed Loop System ◽  
Linear Parameter Varying ◽  
Aerodynamic Derivatives ◽  
Operating Points

An augmented lateral acceleration autopilot is designed for a model of a tactical missile and robust stability of the closed-loop system investigated. The tail-controlled missile in the cruciform fin configuration is modelled as a second-order quasi-linear parameter-varying system. This non-linear model is obtained from the Taylor linearized model of the horizontal motion by including explicit dependence of the aerodynamic derivatives on a state (side-slip velocity) and external parameters (longitudinal velocity and roll angle). The autopilot design is based on input-output pseudolinearization, which is a restriction of input-output feedback linearization to the set of equilibria of the non-linear model. The design makes Taylor linearization of the closed-loop system independent of the choice of equilibria. Thus, if the operating points are in the vicinity of the equilibria, then only one linear model will describe closed-loop dynamics, regardless of the rate of change in the operating points. Simulations for constant lateral acceleration demands show good tracking with fast response time. Robust autopilot design taking into account parametric stability margins for uncertainty aerodynamic derivatives is implemented using convex optimization and linear matrix inequalities.

Flight Control Law Design Using Dynamic Inversion for Linear Parameter Varying Systems

1998 ◽  
Vol 120 (2) ◽  
pp. 200-207 ◽  
Author(s):  
D. Malloy ◽  
B. C. Chang
Keyword(s):  
Flight Control ◽  
Closed Loop ◽  
Broad Class ◽  
Nonlinear Function ◽  
Loop System ◽  
Linear Parameter ◽  
Closed Loop System ◽  
Outer Loop ◽  
Linear Parameter Varying ◽  
Parameter Varying

A regulator design technique is presented for linear parameter varying (LPV) systems. This technique may be applied to many different types of systems, including nonlinear, due to the broad class of systems that may be represented by LPVs. The regulator, consisting of an inner loop and an outer loop, renders the closed-loop system’s steady-state input-output to be linear time invariant (LTI) and causes the output to track a commanded trajectory. With real-time, accurate parameter data, the inner loop effectively cancels the parameter dependent terms. The outer loop is designed using LTI H∞ synthesis to enable the closed loop system to meet stability and performance goals. Due to the inner loop controller and imperfect parameter cancellation, the complete closed-loop system is likely to be a nonlinear function of the parameters and their derivatives. To assess the stability using the quadratic Lyapunov test, we model the closed-loop system as a polytopic system. The key ideas are illustrated with a nonlinear aircraft flight control example.

scholarly journals Design of State-Feedback Controllers for Linear Parameter Varying Systems Subject to Time-Varying Input Saturation

2019 ◽  
Vol 9 (17) ◽  
pp. 3606
Author(s):  
Adrián Ruiz ◽  
Damiano Rotondo ◽  
Bernardo Morcego
Keyword(s):  
State Feedback ◽  
Closed Loop ◽  
Loop System ◽  
Feasibility Problem ◽  
Time Varying ◽  
Linear Parameter ◽  
Closed Loop System ◽  
Linear Parameter Varying ◽  
Quadratic Lyapunov Functions ◽  
Parameter Varying

All real-world systems are affected by the saturation phenomenon due to inherent physical limitations of actuators. These limitations should be taken into account in the controller’s design to prevent a possibly severe deterioration of the system’s performance, and may even lead to instability of the closed-loop system. Contrarily to most of the control strategies, which assume that the saturation limits are constant in time, this paper considers the problem of designing a state-feedback controller for a system affected by time-varying saturation limits with the objective to improve the performance. In order to tie variations of the saturation function to changes in the performance of the closed-loop system, the shifting paradigm is used, that is, some parameters scheduled by the time-varying saturations are introduced to schedule the performance criterion, which is considered to be the instantaneous guaranteed decay rate. The design conditions are obtained within the framework of linear parameter varying (LPV) systems using quadratic Lyapunov functions with constant Lyapunov matrices and they consist in a linear matrix inequality (LMI)-based feasibility problem, which can be solved efficiently using available solvers. Simulation results obtained using an illustrative example demonstrate the validity and the main characteristics of the proposed approach.

P-D Feedback for Decoupling and Pole Assignment of Singular Systems

1998 ◽  
Vol 120 (3) ◽  
pp. 378-388 ◽  
Author(s):  
F. N. Koumboulis ◽  
B. G. Mertzios
Keyword(s):  
Closed Loop ◽  
Singular Systems ◽  
Sufficient Conditions ◽  
Pole Assignment ◽  
Loop System ◽  
Necessary And Sufficient Conditions ◽  
Algebraic Equations ◽  
Input Output ◽  
Closed Loop System ◽  
Necessary And Sufficient

The problem of reducing a multi input-multi output system to many single input-single output systems, namely the problem of input-output decoupling, is studied for the case of singular systems i.e., for systems described by dynamic and algebraic equations. The problem of input-output decoupling with simultaneous arbitrary pole assignment, via proportional plus derivative (P-D) state feedback, is extensively solved. The general explicit expression of all P-D controllers solving the decoupling problem is determined. The general form of the diagonal elements of the decoupled closed-loop system is proven to be in a form having a fixed numerator polynomial and an arbitrary denominator polynomial. The necessary and sufficient conditions for the solvability of the problem of decoupling with simultaneous asymptotic stabilizability or arbitrary pole assignment are established. Furthermore, the necessary and sufficient conditions for decoupling with simultaneous impulse elimination, as well as the necessary and sufficient conditions for decoupling with arbitrary assignment of the finite and infinite poles of the closed-loop system, are established.

Use of Bilinear Structures for Modelling a Brewery Fermentation Process

1996 ◽  
Vol 29 (9) ◽  
pp. 262-265 ◽  
Author(s):  
C.R. Johnson ◽  
K.J. Burnham
Keyword(s):  
Specific Gravity ◽  
Discrete Time ◽  
Fermentation Process ◽  
Closed Loop ◽  
Loop System ◽  
Model Structure ◽  
Bilinear Model ◽  
Input Output ◽  
Closed Loop System ◽  
Model Structures

This paper presents the results of an investigative study with the aim being to obtain and assess the appropriateness of bilinear model structures for replicating the characteristics of a brewery fermentation process. Based on realtime data taken from a brewery fermentation plant, it is shown that a discrete-time twin-bilinear model, which simultaneously relates temperature to specific gravity and specific gravity to temperature, provides an adequate input/output reconstruction. The ability of the twin-bilinear model structure is discussed and possibilities for its utilization with an adaptive closed loop system are considered.

Robust Gain-Scheduling Controller for Airbreathing Hypersonic Flight Vehicle

2014 ◽  
Vol 716-717 ◽  
pp. 1624-1630 ◽  
Author(s):  
Yuan Chuan Shen ◽  
Jian Qiao Yu ◽  
Guan Chen Luo ◽  
Rui Guang Yang
Keyword(s):  
Closed Loop ◽  
Dynamic Performance ◽  
Gain Scheduling ◽  
Flight Vehicle ◽  
Linear Parameter ◽  
Closed Loop System ◽  
Linear Parameter Varying ◽  
Technical Challenge ◽  
Hypersonic Flight Vehicle ◽  
Hypersonic Flight

This paper addresses issues related to robust control for an airbreathing hypersonic flight vehicle. Owing to aero-propulsion couplings caused by the unique structure shape, the model of the vehicle is greatly nonlinear and complex, which presents an enormous technical challenge for control. The nonlinear model is transformed into a linear fractional transformation (LFT) model, and a robust gain-scheduling controller based on linear parameter-varying control (LPV) with full block multipliers is obtained. Simulations illustrate great improvements of the dynamic performance in closed-loop system.

Design and Stability Analysis of a QFT Pressure Controller of a Hydraulic Actuator Using Takagi-Sugeno Fuzzy Model

2015 ◽  
Author(s):  
Masoumeh Esfandiari ◽  
Nariman Sepehri
Keyword(s):  
Stability Analysis ◽  
Closed Loop ◽  
Nonlinear Function ◽  
Loop System ◽  
Performance Criteria ◽  
Parametric Uncertainties ◽  
Hydraulic Actuator ◽  
Closed Loop System ◽  
Takagi Sugeno ◽  
Operating Points

In this paper, a robust, fixed-gain, and linear controller is designed for the output pressure of an electro-hydraulic actuator with parametric uncertainties. Quantitative feedback theory (QFT) is selected as the design technique. The objective is to satisfy specified performance criteria in terms of tracking, stability, and disturbance rejection. To design the QFT controller, the required family of frequency responses is obtained by linearizing the hydraulic nonlinear function around operating points of interest, and constructing an equivalent linear plant set. As a result, the stability of the closed-loop system is guaranteed only around the limited number of operating points, and specified values for system parameters. To overcome this limitation, Takagi-Sugeno (T-S) fuzzy modeling is employed. This way the nonlinear stability of the closed-loop system is investigated and ensured for a continuous range of parametric uncertainties and region of operating points. Having successful results from stability analysis, the QFT controller is applied on the experimental set-up. The experimental results are in accordance with the specified criteria.

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