Finite dimensional adaptive H∞ control for flexible arms preceded by input nonlinearites

The problem of constructing model reference adaptive H_∞ control for flexible arms preceded by unknown input nonlinearities such as dead-zone or backlash, is considered in this paper. Control schemes of flexible arms are mixed parameter systems composed of distributed parameter systems of hyperbolic type (flexible arms) and lumped parameter systems (motor control systems). An adaptive inverse model is introduced to estimate and compensate input nonlinearities. The stabilizing control signal is added to regulate the effect of spill-over terms, and it is derived as a solution of certain H_∞ control problem where the residual part of the inverse model and the spill-over term are considered as external disturbances.