A stability analysis of controllers subject to amplitude and rate constraints

This paper investigates the problem of actuators subject to both amplitude and rate constraints. Previous works studied these saturation types separately. Here a compensation structure catering to both constraints is proposed. Realizability of the compensator and its necessary conditions to maintain linear stabilities are presented, conforming to other established results. A simple design method of combining two individually selected compensators is proposed. Discussions focus on analysis of nonlinear stability when both saturations occur simultaneously. The analysis resorts to an approximation of frequency domain methods, enabling necessary conditions for asymptotic stability to be investigated A numerical example demonstrates the procedures and success of the proposed method