An improved adaptive T-S fuzzy observer for arc length observing
改进的电弧弧长自适应T-S模糊观测器

The design of the adaptive observer based on the Lyapunov method commonly requires that the system satisfies constraints of Kalman-Yakubovitch-Popov(KYP) theorem. Therefore, by adding an auxiliary variable to relax this constraint, this paper presents an improved adaptive observer for nonlinear systems with unknown parameters. This method is applied to design an observer for the arc length in a gas-metal arc welding system. The arc length is effectively estimated on condition that the distance between the welding tip to the work piece is unknown. Simulation results show the effectiveness of this approach.