Prescribed Performance Output Feedback Adaptive Control of Uncertain Strict Feedback Nonlinear Systems

摘要

An output feedback prescribed performance control design is presented for a class of strict feedback uncertain nonlinear systems. To overcome state unavailability an "estimator-like" system is introduced, which generates rough estimates of the unknown signals, thus avoiding the demanding task of constructing asymptotically convergent observers. Moreover this control approach avoids posing severe restrictions on the unknown system nonlinearities other than their continuity. To effectively avoid possible division by zero, the designed output feedback controller is of switching type. However, its continuity is guaranteed, thus alleviating any problems related to the existence and uniqueness of solutions. Simulations on a single-link manipulator actuated by a brush dc motor benchmark example illustrate the approach.