Composite Robust Control of a Laboratory Flexible Manipulator

This paper presents laboratory control experiments on a two-dof flexible link manipulator using optimal and robust methods. Considering the flexible mechanical structure as a system with slow and fast modes, the system dynamics is decomposed into a slow and a fast subsystem that can be controlled separately. Two experimental robust control approaches are considered. In a first test an LQR optimal design strategy is used, while a second design includes a sliding-mode structure for the slow subsystem. Experimental results are compared with conventional rigid control schemes and show that this composite approach achieves good closed-loop tracking properties for both design philosophies.