Abstract: This paper develops a fuzzy state estimate-based robust adaptive control scheme for a class of mechanical systems with multiple degrees of freedom. The unmeasurable state variables used in both modeling friction force and adaptive controller design are estimated by a fuzzy estimator. By strictly positive real lemma and Lyapunov stability theory, the ultimately uniform boundedness of the state estimation errors is ensured. This paper also proposes a multivariable robust control algorithm using the estimated states and adaptive fuzzy friction mode, where the updating rule for parameter adjustment in the fuzzy friction model is derived by Lyapunov theory. It is shown that the tracking error of the closed-loop system is ultimately uniformly bounded (UUB). A mass-spring-damping system with multiple degrees of freedom is employed in the simulation studies. Simulation results demonstrate the effectiveness of our proposed state-estimate based fuzzy friction modeling and adaptive control strategy.