Description

Smart materials, such as piezoelectric and magnetostrictive materials and shape memory polymers, have inherent capabilities to respond to an external stimulus in a functionally useful manner. Actuators made of smart materials are capable of operating at high frequency with high precision. In recent years, the demand for these actuators has increased rapidly, as technology advances and more industrial applications are found. There are various controller strategies discussed in literature for such systems, including PID, non-linear, adaptive, and hybrid controllers. However, various nonlinearities limit the control to a fraction of the potential operating region. In this talk, Dr. Ekanayake will introduce some applications of smart actuators and will discuss the development of a trajectory tracking controller capable of improving the dynamical performance of high precision positioning systems. In the case of magnetically controlled smart actuators, one can utilize both position feedback and induced voltage feedback. However, input disturbances become a significant part of the input current, and the tracking control must achieve the objectives while keeping the input current within its rated conditions. Here, the sufficient conditions on controller parameters are derived for ultimate bounded control while maintaining both the input current within the rated conditions and the closed-loop system stability for bounded input disturbance signals.