A direct method for robust adaptive nonlinear control with guaranteed transient performance

In this paper, the adaptive control problem is studied for a class of nonli near systems in the presence of bounded disturbances. By utilizing a nice p roperty of the studied systems, a novel Lyapunov-based control structure is developed, which avoids the possible control singularity problem in adapti ve nonlinear control. The transient bounds of output tracking error are sho wn to be explicit functions of initial conditions and design parameters, an d the control performance of the closed-loop system is guaranteed by suitab ly choosing the design parameters. Simulation study is provided to verify t he theoretical results. (C) 1999 Elsevier Science B.V. All rights reserved.