Three-Axis Autopilot Design for a High Angle-Of-Attack Missile Using Mixed H₂/H_∞Control

Abstract

The increased demand for high maneuverability of modern missiles requires excellent autopilot performance over a large flight envelope. The main difficulty in missile autopilot design is the influence of high angle-of-attack aerodynamic phenomena on stability characteristics (Hemsch, 1992). As a missile executes a high angle-of-attack maneuver, the forebody vortices can become asymmetric and give rise to significant lateral-forces and yawing moments. Classically, missile autopilots are designed using gain scheduling approaches in roll, pitch, and yaw channels (Blakelock, 1991;Shamma and Athans, 1992;Shamma and Cloutier, 1993;White et al., 2007). However, the performance of singleaxis autopilot design approaches are limited within some flight boundaries because aerodynamic coupling effects and their parameter dependencies in large angle-of-attack aerodynamics could not be considered. In this context, the design of a three-axis missile autopilot has been studied using linear and nonlinear control approaches (Choi et al., 2008;Devaud et al., 2001;Kim et al., 2008). These methods are based on gain scheduling techniques by local linearization, and demonstrate some improvements from a practical point of view.In this paper, a three-axis missile autopilot design with a multi-objective output-feedback control theory is presented. Because high angle-of-attack aerodynamics is highly nonlinear and estimates of the aerodynamic coefficients are very imprecise, a mix of H∞ and H2 criteria is employed to guarantee the performance of the three-axis missile autopilot. This control methodology, which uses linear matrix inequality (LMI) techniques, was motivated by the work in (Schere et al., 1997). This paper is organized as follows. In Section 2, we give an overview of multi-objective output-feedback control theory. Section 3 describes our formulation of the missile control problem. Section 4 describes strategies and numerical simulation results for the designed autopilot. Our conclusions are provided in Section 5. AbstractWe report on the design of a three-axis missile autopilot using multi-objective control synthesis via linear matrix inequality techniques. This autopilot design guarantees H 2 /H ∞ performance criteria for a set of finite linear models. These models are linearized at different aerodynamic roll angle conditions over the flight envelope to capture uncertainties that occur in the high-angle-of-attack regime. Simulation results are presented for different aerodynamic roll angle variations and show that the performance of the controller is very satisfactory.

Flight optimisation of missile using linear matrix inequality (LMI) approach

“…The LMI problem of the output feedback is in the form of (32) satisfying (5)–(15). The next step is followed: Upon formulation of the LMI, the computation executes as follows: (i) Depiction of non‐singular matrix M , N satisfying the M N ℽ = I − XY via singular value decomposition [8]. (ii) Solve the linear equations for K ( s ) controls as follows: …”

A probabilistic robust mixed H2/H∞ fuzzy control method for hypersonic vehicles based on reliability theory

“…It is assumed that z 1 2 ½8; 10; z 2 2 ½3:5; 4, and z 3 2 ½60; 000; 80; 000 according to the reentry conditions. We select the following 2 3 operating points to construct the local linear model 1 denote the fuzzy sets "about 8" and "about 10" for z 1 , respectively. Let F 1 2 and F 2 2 denote the fuzzy sets "about 3.5" and "about 4" for z 2 , respectively.…”

“…In recent years, various techniques have been studied for dealing with parameter variations and uncertainties, such as robust control, [1][2][3] adaptive control, 4 sliding mode control, [5][6][7][8] and so on. For example, H 1 control theory was developed for the precision guidance problem by Savkin.…”

Agile Missile Autopilot Design using Nonlinear Backstepping Control with Time-Delay Adaptation

“…For the separation and the terminal homing phase, the body rate and the body acceleration commands are typically recommended, respectively. For the agile turn phase, two options such as the body acceleration [3][4][5][6][7][8][9] and the angle-of-attack, 1,[10][11][12][13] are possible autopilot command structures. According to Ref.…”

“…For highly agile missile systems, other robust control methodologies have been applied to the design of missile autopilot based on H 1 control, 4) "-synthesis 5,6) and mixed H 2 =H 1 control synthesis. 7) The authors in Ref. 8) proposed missile autopilot design, using feedback linearization and a two-time scale separation technique.…”