Global tunability of one-dimensional SISO systems

It is shown by example that with a suitably defined certainty equivalence controller Sigma /sub R/, it is possible to make a closed-loop parameterized system Sigma tunable on its entire parameter space P, even though P may contain points at which the parameterized Sigma /sub D/, upon which Sigma /sub R/'s definition is based, is not stabilizable. The implications of this discovery are briefly discussed.<
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