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Flexible structures have been increasingly utilized in many applications because of their light-weight and low production cost. However, being flexible leads to vibration problems. Vibration suppression of flexible structures is a challenging control problem because the structures are actually infinite-dimensional systems. In this paper, an adaptive control scheme is proposed for the vibration suppression of a piezo-actuated flexible beam. The controller makes use of the configuration of the prominent proportional-integral-derivative controller and is derived using an infinite-dimensional Lyapunov method. In contrast to existing schemes, the present scheme does not require any approximated finite-dimensional model of the beam. Thus, the stability of the closed loop system is guaranteed for all vibration modes. Experimental results have illustrated the feasibility of the proposed control scheme. [ABSTRACT FROM AUTHOR]

This paper presents an application of fractional-order control to industrial electrohydraulics. An optimization based frequency domain approach is used to obtain a fractional-order proportional-integral controller for force control of an electrohydraulic actuator. The controller is designed to have a feature of robustness to gain variations with the step responses exhibiting an iso-damping property. In practice, the gain variations are due to the changes in the environment or the load's force interacting with the actuator. Results of real life experiments demonstrate the effectiveness of the controller. [ABSTRACT FROM AUTHOR]