| Summary: | 博士 === 國立清華大學 === 電機工程學系 === 89 === Recently, the nonlinear H-infinity control schemes have been
introduced to deal with the robust performance design problem of
nonlinear systems. However, the designer has to solve a
Hamilton-Jacobi equation, which is a nonlinear partial
differential equation. Only some very special nonlinear
systems have a closed form solution. In general, conventional nonlinear
H-infinity control schemes are not suitable for practical
control system design. Based on the Takagi and Sugeno (TS) fuzzy
model, both state feedback and output feedback decentralized
fuzzy tracking control designs with a guaranteed H-infinity
tracking performance will be addressed in this dissertation for a
multi-arm system. A fuzzy observer-based control design will be
employed to deal with the output feedback control problem. By the
proposed method, the outcome of the fuzzy tracking control design
problem can be parameterized in terms of a linear matrix
inequality problem (LMIP) or an eigenvalue problem (EVP). The
LMIP or EVP can be solved very efficiently using the convex
optimization techniques. Systematical design procedure using LMI
techniques is proposed to implement the H-infinity fuzzy
tracking control problems. The results of the proposed
H-infinity decentralized fuzzy tracking controller are applied
to a multi-arm system. The main results are summarized as
follows: First, this dissertation introduces a fuzzy control
design method for nonlinear systems with a guaranteed
H-infinity model reference tracking performance. First, the
Takagi and Sugeno (TS) fuzzy model is employed to approximate a
nonlinear system. Next, based on the fuzzy model, a fuzzy
controller is developed to reduce the tracking error as small as
possible for all bounded reference inputs. If the state variables
are unavailable, a fuzzy observer-based tracking control design
is also developed. The advantage of proposed tracking control
design is that only a simple linear fuzzy controller is used in
our approach without complicated feedback linearization technique
and adaptive scheme. By the proposed method, the fuzzy tracking
control design problem is parameterized in terms of a linear
matrix inequality problem (LMIP). The LMIP can be solved very
efficiently using the convex optimization techniques. Simulation
examples are given to illustrate the design procedures and
tracking performance of the proposed method. Second, it is not
easy to design an H-infinity decentralized controller for
nonlinear interconnected systems in general. In this
dissertation, the tracking control problem of nonlinear
interconnected systems is studied via H-infinity decentralized
fuzzy control method. Similarly, the nonlinear interconnected
system is represented by an equivalent Takagi-Sugeno type fuzzy
model. A state feedback decentralized fuzzy control scheme is
developed to achieve the H-infinity tracking performance.
Furthermore, the stability of the nonlinear interconnected
systems is also guaranteed. This design problem is equivalent to
solving an eigenvalue problem (EVP). Third, due to the physical
configuration and high dimensionality of the constrained
multibody systems, a centralized fuzzy control is neither
efficient nor even necessary. Therefore, a decentralized fuzzy
control scheme is more suitable for the constrained multibody
systems. In this dissertation, an H-infinity decentralized fuzzy
tracking control scheme is proposed for a constrained multibody
system. Finally, in order to illustrate the design effectiveness
of the proposed H-infinity decentralized fuzzy tracking control
scheme, an experimental multi-arm system with fully digital
controller is setup to confirm the tracking performance.
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