Unified Adaptive Control of Uncertain MIMO Nonlinear Systems With Diverse Performance Under Different Initial Conditions

In this paper, a unified adaptive tracking control scheme for uncertain multi–input multi–output (MIMO) nonlinear systems with diverse performance is studied. Firstly, to obtain high–precision prescribed performance tracking control, some well–defined functions are utilized to design the precise performance boundaries. Secondly, to cater to different initial conditions, the tailored scaling function is further exploited to construct the unifying performance boundaries. With such a treatment, the diverse performance could be obtained by the simple parameter selection under a fixed control structure. Furthermore, a special nonlinear mapping function is constructed to cope with the specific one–sided precise performance boundaries and the common two–sided standard ones in a unified way. Finally, a robust adaptive controller is synthesized to ensure the tracking error evolves within the unifying performance boundaries strictly and enters a predefined region within a preassigned settling time irrespective of any initial values. The efficacy of the proposed control scheme is verified by rigorously theoretical analysis and some numerical simulations.