ABSTRACT
In general, an automatic controller compares the actual output of the plant with the reference input (desired value), and hence produces a control signal that will reduce the deviation between the actual and desired values to zero or to a small value. Figure 2.1 presents a block diagram of a typical control system that is integrated with piezoelectric actuators. The controller detects the actuating error signal that is usually at a very low power level, and amplifi es it to a suffi ciently high level via the voltage (or current) amplifi er for the actuators. The actuator is a power device that produces the input to the application device according to the control signal. Piezoelectric actuators are used in the active control system. Control energy cannot only be taken away, but also be inserted into the plant with the active type of actuator. Most of the currently available sensors such as accelerometer can be adapted to measure dynamic responses of the control system associated with piezoelectric actuators. In this chapter, some control methodologies that are very effective in controlling the system featuring piezoelectric actuators are introduced.
