Dual-scale direct learning control of trajectory tracking for a class of nonlinear uncertain systems

In this paper the authors present a new learning control scheme: dual-scale direct learning control for trajectory tracking problems. Direct learning control (DLC) is defined as the direct generation of the desired control input profile from existing control input profiles without any repetitive learning. The DLC schemes developed hitherto are capable of learning the desired control signals for the new trajectory from past tracking control profiles which correspond to trajectories with either nonuniform time scales or nonuniform magnitude scales. Here the authors further show that for a class of nonlinear uncertain dynamic systems, the proposed dual-scale DLC scheme is able to generate the desired control input profile for a new trajectory which differs from all of the previously controlled and stored trajectories in both time and magnitude scales