Nonlinear sampled control laws of a robot with flexible links

A model of a flexible structure composed of two links, considered as Euler-Bernouilli beams and spatially discretized using the assumed mode method is briefly presented. A continuous-time nonlinear control law is recalled, which decouples nd linearizes the input output behaviour. The implementation of this control law requires the introduction of a digital computer generating a sampled control law. Holding the continuous-time control during each sampling interval leads, in the case considered here, to the loss of the stability properties. Therefore different nonlinear discrete-time control laws are used: they are based on discretization procedures obtained by means of the exponential of formal Lie derivatives. >