CONSTRAINED H-INFINITY CONTROL OF AN EXPERIMENTAL FLEXIBLE LINK

A new approach is presented to design robust controllers for an experi mental flexible beam with noncolocated sensors-actuator. The objective is to position the free end of the beam in the specified time under t ight bounds on the trajectory of the tip and control action. We derive a transfer function nominal model for the beam and a quantitative des cription of model uncertainties based on experimentally obtained frequ ency response data. Robust controllers are designed by applying the re cently developed Constrained H-infinity control approach (Sideris and Rotstein, 1993, 1994), in which time-domain constraints are treated di rectly without translation to the frequency-domain. Constrained H-infi nity controllers are compared with standard H-infinity and mu-synthesi s designs in terms of both simulation and experimental results and are found to be superior in the considered case of stringent time-domain specifications.