Highly Dynamic Piezoelectric Positioning

Even tough piezoelectricity was already discovered in 1880, it was only over the course of the past 20 years that the use of piezoelectric materials for positioning applications has increased significantly. Until now, piezoelectric actuators are mainly used in high-precision applications with little demand for highly dynamic operation. Nevertheless, there is a clearly increasing number of positioning applications that do require highly dynamic operation as well. To account for the new challenges for the control of piezoelectric actuators introduced by these applications, the main focus of this thesis is on establishing the prerequisites for highly dynamic positioning. In this regard, two key building blocks for combining highly dynamic operation with high-precision positioning have been covered: power amplifiers for piezoelectric actuators and control of piezoelectric systems.

First, the most suitable power amplifiers are derived for various types of positioning applications. This led to the development of a new topology: the UBiCS converter, which is also described. Then, design rules are established and it is shown how the amplifiers can be controlled.

Linear and nonlinear control designs for piezoelectric systems are distinguished. For linear control designs, it is shown to which degree the performance of the specific control deteriorates due to the nonlinearities of piezoelectric actuators. This is compared to the performance that can be achieved using control techniques that account for the nonlinearities. Finally, the optimal control design for highly dynamic positioning applications is identified.