Adaptive control of flexible-joint robots

The problem of designing robust adaptive control strategies for a flexible-joint robot manipulator is considered. By utilizing the concept of integral manifolds, a corrected reduced-order model of the flexible system is obtained. Adaptive control schemes for the corrected reduced-order model are then developed that otherwise would have been difficult to obtain for the full-order flexible system due to ill conditioning and the curse of dimensionality. Zeroth-order singular perturbation results are generalized to include corrected adaptive control schemes. The result is a robust adaptive control law that takes both parametric and dynamic uncertainties into account. Two common adaptive control strategies, the adaptive inverse dynamics scheme and the Slotine and Li (1987) scheme, are examined. Numerical simulations for a two-link flexible-joint manipulator are carried out to illustrate the potential and advantages of the adaptive control schemes as compared to these two techniques