果冻传媒

A distinction can be made based on motion range (鈥渓ong鈥� indicating meter-scale, 鈥渟hort鈥� indicating mm scale), and accuracy (micrometer or sub-nanometer). Long-range actuators typically have a moderate accuracy but suffer from nonlinearities like friction, requiring compensation methods using adaptive or learning techniques. Nonlinearities also play a role when using piezo materials for actuation in high-accuracy applications, possibly simultaneously with using the material as sensor (鈥渟elf-sensing鈥�). Finally, control techniques to improve sub-nanometer positioning systems have to deal with position dependency, in particular in the observation of dynamic modes in the measurement system. This has led to position-dependent observers creating the option of increasing control bandwidth.