The convergence of parameter estimates and the real structure information of plant are both unnecessary for a general self-tuning control system - Arbitrary deterministic plant

This paper is concerned with the stability and convergence of a general deterministic self-tuning control (STC) system, which consists of arbitrary control strategy and arbitrary estimation algorithm. The plant may be linear or non-linear, time-invariant or time varying. The conditions required for global stability and convergence are relaxed, i.e., the convergence of parameter estimates and the real structure information of plant are both removed. It is therefore argued that external excitation signal is not necessary for deterministic STC system. In other words, feedback information of STC system itself is sufficient to achieve the control objective (regulation or tracking). The key point is that with the help of Virtual Equivalent System (VES) concept, the original nonlinear dominant (nonlinear in structure) problem of STC is converted to a linear dominant (linear in structure) problem-deterministic slow switching control system.