NONLINEAR H* METHOD FOR CONTROL OF UNCERTAIN WING ROCK MOTIONS
NONLINEAR H* METHOD FOR CONTROL OF UNCERTAIN WING ROCK MOTIONS
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发表时间:
1998
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通讯作者:
S. Shue;Peng Shit;R. Agarwal;M. E. Sawan
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作者:
S. Shue;Peng Shit;R. Agarwal;M. E. Sawan
Control of nonlinear wing rock motion of slender delta wings using nonlinear H^ robust method is presented in this paper. The wing rock motion is mathematically described by a nonlinear ordinary differential equation with coefficients varying with angle of attack. In the time domain approach, the nonlinear Ha robust control problem with state feedback is cast in terms of a Hamilton-Jacobi-Bellman inequality (HJBI). Assuming that the coefficients in nonlinear equation of wing rock motion satisfy a norm bounded nonlinear criterion, the HJBI can be written in a matrix form. The state vector is represented as a series of closed loop Lyapunov functions (CLLF) which result in reducing the HJBI to an algebraic Riccati inequality along with several other algebraic inequalities. These inequalities can be successively solved to a desired power in the series representation of the state vector in the HJB equation. The results of the nonlinear H^ state feedback control are compared with these obtained with the linear H „ state feedback control indicating the necessity of employing nonlinear feedback control for nonlinear dynamics. L INTRODUCTION At high angle of attack, flowfield of a slender delta wing is characterized by a strongly organized vortical flow emanating from its strong leading edges. The vortex sheets emanating from the leading edges roll into a pair of vortices. As the angle of attack increases, these vortices interact with each other and