AN ELASTODYNAMIC ANALYSIS AND CONTROL OF FLEXIBLE LINKAGES USING PIEZOCERAMIC SENSORS AND ACTUATORS

This paper presents an analytical and experimental study on the elasto dynamic analysis and control of flexible linkage mechanisms using piez oceramic sensors and actuators. A mixed variational principle is devel oped to provide the basis for deriving the finite element equations wh ich govern the dynamic responses of the flexible links, behavior of th e piezoelectric materials and their coupling relationships, while bein g subjected to both mechanical and electric boundary conditions. The p iezoceramic devices featuring the characteristics of smart materials c apable of sensing and controlling elastodynamic responses of the flexi ble links are employed in an LQG/LTR (Linear Quadratic Gaussian with L oop Transfer Recovery) control scheme to ensure a stable performance. Finally, a four-bar linkage mechanism with one flexible link is utiliz ed as an illustrative example. The results show that the midspan vibra tion of the flexible link has been greatly suppressed and the control/ observer spillover-induced instability has been avoided.