Symbol-type adaptive fuzzy controller
符号型自适应模糊控制器

The design of contraction-expansion factor is crucial in variable universe fuzzy control. Using Lyapunov synthetic analysis, we propose an adaptive fuzzy control with sign function to avoid the design of contraction-expansion factor. In this scheme, the stretch operator of control input employs the sign function instead of the exponential function or the scale function employed in variable universe fuzzy control design, and the consequence adjustment still uses an integral regulation. Compared with the variable universe fuzzy control, the proposed scheme is essentially a kind of fuzzy control with variable universe with less fuzzy rules, higher steady precision and higher robustness to external disturbance. Lyapunov stability theory guarantees the asymptotic convergence of tracking error. A simulation example shows the efficacy of the proposed scheme.