In this paper we consider the problem of force control through a constrained flexible beam. The H-infinity loopshaping design paradigm is used in an attempt to obtain controllers that are insensitive to the exact position of the constraint. Although the controllers generated by this design approach possess a number of desirable features we demonstrate how easy it is to obtain unacceptable controllers if the properties of the plant are not given due consideration. We then show how the delta(nu)-gap metric introduced by Vinnicombe (1993) can be used to incorporate parametric uncertainty into the H-infinity-loopshaping design paradigm. Using this metric, and suitable switching techniques, controllers are designed to cover large variations in the open-loop dynamics that result from significant changes in the position of the constraint. Finally, these controllers are implemented and evaluated on an experimental system.