### Abstract

We propose an adaptive output feedback control design for global asymptotic stabilization of feedforward systems based on our recent results on dynamic highgain scaling based controller design for strict-feedback systems. The system is allowed to contain uncertain functions of all the states and the input as long as they satisfy certain bounds. Unknown parameters are allowed in the bounds assumed on uncertain functions. If the uncertain functions involve the input, then the output-dependent functions in the bounds need to be polynomially bounded. It is also shown that if the uncertain functions can be bounded by a function independent of the input, then the polynomial boundedness requirement can be relaxed. The designed controllers have a simple structure being essentially a linear feedback with state-dependent dynamic gains and do not involve any saturations or recursive computations. The observer utilized to estimate unmeasured states is similar to a Luenberger observer with dynamic observer gains. The Lyapunov functions are quadratic in state estimates, observer errors, and parameter estimation error. The stability analysis is based on our recent results on uniform solvability of coupled state-dependent Lyapunov equations. The controller provides strong robustness properties both with respect to uncertain parameters and additive disturbances. This robustness is the key to the output feedback controller design.

Original language | English (US) |
---|---|

Title of host publication | 2004 5th Asian Control Conference |

Pages | 2039-2047 |

Number of pages | 9 |

Volume | 3 |

State | Published - 2004 |

Event | 2004 5th Asian Control Conference - Melbourne, Australia Duration: Jul 20 2004 → Jul 23 2004 |

### Other

Other | 2004 5th Asian Control Conference |
---|---|

Country | Australia |

City | Melbourne |

Period | 7/20/04 → 7/23/04 |

### Fingerprint

### ASJC Scopus subject areas

- Engineering(all)

### Cite this

*2004 5th Asian Control Conference*(Vol. 3, pp. 2039-2047)

**Dynamic high gain scaling : An application to robust adaptive output feedback for feedforward systems.** / Krishnamurthy, P.; Khorrami, Farshad.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*2004 5th Asian Control Conference.*vol. 3, pp. 2039-2047, 2004 5th Asian Control Conference, Melbourne, Australia, 7/20/04.

}

TY - GEN

T1 - Dynamic high gain scaling

T2 - An application to robust adaptive output feedback for feedforward systems

AU - Krishnamurthy, P.

AU - Khorrami, Farshad

PY - 2004

Y1 - 2004

N2 - We propose an adaptive output feedback control design for global asymptotic stabilization of feedforward systems based on our recent results on dynamic highgain scaling based controller design for strict-feedback systems. The system is allowed to contain uncertain functions of all the states and the input as long as they satisfy certain bounds. Unknown parameters are allowed in the bounds assumed on uncertain functions. If the uncertain functions involve the input, then the output-dependent functions in the bounds need to be polynomially bounded. It is also shown that if the uncertain functions can be bounded by a function independent of the input, then the polynomial boundedness requirement can be relaxed. The designed controllers have a simple structure being essentially a linear feedback with state-dependent dynamic gains and do not involve any saturations or recursive computations. The observer utilized to estimate unmeasured states is similar to a Luenberger observer with dynamic observer gains. The Lyapunov functions are quadratic in state estimates, observer errors, and parameter estimation error. The stability analysis is based on our recent results on uniform solvability of coupled state-dependent Lyapunov equations. The controller provides strong robustness properties both with respect to uncertain parameters and additive disturbances. This robustness is the key to the output feedback controller design.

AB - We propose an adaptive output feedback control design for global asymptotic stabilization of feedforward systems based on our recent results on dynamic highgain scaling based controller design for strict-feedback systems. The system is allowed to contain uncertain functions of all the states and the input as long as they satisfy certain bounds. Unknown parameters are allowed in the bounds assumed on uncertain functions. If the uncertain functions involve the input, then the output-dependent functions in the bounds need to be polynomially bounded. It is also shown that if the uncertain functions can be bounded by a function independent of the input, then the polynomial boundedness requirement can be relaxed. The designed controllers have a simple structure being essentially a linear feedback with state-dependent dynamic gains and do not involve any saturations or recursive computations. The observer utilized to estimate unmeasured states is similar to a Luenberger observer with dynamic observer gains. The Lyapunov functions are quadratic in state estimates, observer errors, and parameter estimation error. The stability analysis is based on our recent results on uniform solvability of coupled state-dependent Lyapunov equations. The controller provides strong robustness properties both with respect to uncertain parameters and additive disturbances. This robustness is the key to the output feedback controller design.

UR - http://www.scopus.com/inward/record.url?scp=16244406264&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=16244406264&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:16244406264

SN - 0780388739

SN - 9780780388734

VL - 3

SP - 2039

EP - 2047

BT - 2004 5th Asian Control Conference

ER -