Adaptive nonlinear ℋ∞ control for processes with bounded variations of parameters

A new class of adaptive nonlinear ℋ_∞ control systems for processes with bounded variations of time-varying parameters, is proposed in this manuscript. Those control schemes are derived as solutions of particular nonlinear ℋ_∞ control problems, where unknown system parameters are regarded as exogenous disturbances to the processes, and thus, in the resulting control systems, the L² gains from system parameters to generalized outputs are made less than γ(>0). The control schemes are suboptimal to some ℋ_∞ cost functionals, when the high-frequency gains are time-invariant