The aim of the present paper is to formulate a simple model of a flexible robotic structure and to propose a class of control strategies based on the sliding modes concept, which appear to be particularly effective in this context. In particular three different approaches will be presented. Each of them clarifies the possible exploitation of sliding modes to damp vibration when both velocities and positions are available for measurements, and in the case in which only elastic forces are known. Since in real cases the delay of propagation of the actuation forces does not allow an ideal sliding mode control and leads to oscillations. In the last part of the paper a control strategy that consists of a discontinuous control law with adaptive gain will be proposed. It also allows damp oscillations in the presence of delay, whereas the classic sliding-modes approach fails. A comprehensive simulation analysis will be provided to complement the theoretical discussion. ©1997 John Wiley & Sons, Inc.