A composite controller which uses a direct fuzzy adaptive control law as the slow control term is proposed to solve the problem of trajectory tracking by a two-link flexible-joint manipulator which is subject to large parametric uncertainties and modeling errors. The strategy uses a novel direct adaptation mechanism based on fuzzy logic that adjusts the gains of the slow control term to yield good trajectory tracking performance in the presence of adverse conditions. The fuzzy adaptive system calculates time-varying control parameters in response to tracking errors between the actual plant outputs and the outputs of a reference model, then adapts the control gains to reduce tracking errors. Simulation results obtained from tracking a square trajectory by a manipulator modeled with both the well-known linear joint stiffness model and a newly developed nonlinear joint stiffness model established that the proposed control strategy effectively manages significant uncertainties and modeling errors in the plant, by time varying the control parameters accordingly.

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Persistent URL dx.doi.org/10.2514/1.57585
Journal Journal of Guidance, Control, and Dynamics
Ulrich, S, & Sasiadek, J. (2013). Engineering Notes : Direct fuzzy adaptive control of a manipulator with elastic joints. Journal of Guidance, Control, and Dynamics, 36(1), 311–319. doi:10.2514/1.57585