This paper studies the problem of global decentralized control by output feedback for large-scale uncertain systems whose subsystems are interconnected not only by their outputs but also by their unmeasurable states. We show that under a linear growth condition, there is a decentralized output feedback controller rendering the closed-loop system globally exponentially stable. This is accomplished by extending an output feedback domination design that requires only limited infor- mation about the nonlinear system. We will apply our design to lower, upper, and non-triangular nonlinear systems. The significance of our results is that we do not need to have prior information about the nonlinearities of the system. Furthermore, we need to only employ a linear observer in combination with a linear controller to stabilize the system. A time-varying output feedback con- troller is also constructed for use with large-scale systems that have unknown parameters. 1. Introduction. Decentralized control of interconnected systems has been an area of considerable research due to its obvious practical application to current prob- lems in the field of controls. Large-scale systems have very complex dynamic models due to the uncertain environment, the varying system parameters, and the intercon- nected structure of the system. Also it is inevitable that nonlinearities are prevalent throughout the dynamics of the interconnected systems. All these issues make the stabilization of such large-scale systems a difficult control problem. Though quite challenging, the research of large-scale systems are relevant to such areas as commu- nication networks, satellite constellations, and the formation control of autonomous vehicles. The research of large-scale nonlinear systems began in the late 1960's and early 1970's. One of the earliest investigations into the nonlinear issues of large-scale sys- tems centered around time-varying stabilization (2). The early research in (7) demon- strated a method of using high-gain state feedback to stabilize the nonlinearities of the large-scale systems. The research in the early 1980's focused on the use of state feedback to globally stabilize large-scale nonlinear systems. Adaptive control was ap- plied in (3) to stabilize a class of large-scale nonlinear systems with success. Output feedback had also been applied to linear large-scale system in such papers as (1), (15),
[1]
D. Konik,et al.
On stabilization of decentralized dynamic output feedback systems
,
1984
.
[2]
A. Linnemann.
Decentralized control of dynamically interconnected systems
,
1984
.
[3]
Mark W. Spong,et al.
Underactuated mechanical systems
,
1998
.
[4]
Wei Lin,et al.
Global regulation of a class of uncertain nonlinear systems using output feedback
,
2003,
Proceedings of the 2003 American Control Conference, 2003..
[5]
X. Xia,et al.
Nonlinear observer design by observer error linearization
,
1989
.
[6]
Boris Lohmann,et al.
Output feedback decentralized control of large-scale systems using weighted sensitivity functions minimization
,
2002,
Syst. Control. Lett..
[7]
L. Praly.
Asymptotic stabilization via output feedback for lower triangular systems with output dependent incremental rate
,
2001,
Proceedings of the 40th IEEE Conference on Decision and Control (Cat. No.01CH37228).
[8]
Arthur J. Krener,et al.
Linearization by output injection and nonlinear observers
,
1983
.
[9]
Zhong-Ping Jiang,et al.
Decentralized and adaptive nonlinear tracking of large-scale systems via output feedback
,
2000,
IEEE Trans. Autom. Control..
[10]
S. Jain,et al.
Decentralized adaptive output feedback design for large-scale nonlinear systems
,
1997,
IEEE Trans. Autom. Control..
[11]
A. Krener,et al.
Nonlinear observers with linearizable error dynamics
,
1985
.
[12]
Petros A. Ioannou.
Decentralized adaptive control of interconnected systems
,
1986
.
[13]
Da-Zhong Zheng.
Decentralized output feedback stabilization of a class of nonlinear interconnected systems
,
1989
.
[14]
Zhong-Ping Jiang,et al.
Decentralized nonlinear output-feedback stabilization with disturbance attenuation
,
2001,
IEEE Trans. Autom. Control..
[15]
Wei Lin,et al.
Output feedback control of a class of nonlinear systems: a nonseparation principle paradigm
,
2002,
IEEE Trans. Autom. Control..
[16]
Hassan K. Khalil,et al.
DECENTRALIZED STABILIZATION OF INTERCONNECTED SYSTEMS USING OUTPUT FEEDBACK.
,
1985
.
[17]
Hassan K. Khalil,et al.
Decentralized stabilization of nonlinear interconnected systems using high-gain feedback
,
1982
.