A fractional-order controller for single-link flexible robots robust to sensor disturbances

Abstract

This work presents a new methodology for the design of the positioning control of single-link flexible manipulators which present only one vibration mode in their dynamics. In this work, the standard phase-lead compensator will be extended to a fractional-order compensator which will be used to minimize the vibrations of the flexible-link. The control objective is the precise positioning of the link tip by combining a precise motor positioning as well as reducing large part of the flexible-link vibration. The control strategy is based on combining a feedforward term and a feedback fractional-order controller. The methodology proposed in this work deals with two perturbations which are usually present in strain gauges, which are sensor habitually used to close feedback control loops of flexible link manipulators. These perturbations are: 1) the high frequency noise and 2) the offset of the signal. Experimental results illustrate the performance of the proposed controller and the advantages that this new design methodology provides.