Adaptive Control of Nonlinear Self-Oscillating Systems using MRAS Technique

This paper presents a model reference adaptive system (MRAS) using Liapunov synthesis applied to a nonlinear oscillator to achieve adaptive control. By considering important properties of the reference model describing a nonlinear oscillator it is possible to manipulate the mathematical equation of the adapted oscillator to derive the error-equation in a form which is linear in the state variables. The method then proceeds along lines similar to the linear case. The nonlinear spring and damping characteristics of the plant need not be known, and the plant is not linearized. The technique is simulated using an adaptive autopilot for a ship.