Vibration control to reduce vibrations Vibration problems are often encountered, both in everyday life (e.g. the heavy noise of an unbalanced washing machine) as well as in technical projects (e.g. an image of a microscope being blurred by vibrations due to people walking by). The aim of vibration control is to reduce unwanted vibrations.
Passive and active vibration control Vibration control can be split up into passive and active methods. Active methods require an external power source, whereas passive methods do not.
Passive vibration control methods directly deal with the physical properties of a mechanical structure, like its stiffness, mass, and damping. Passive vibration control often is a matter of clever (re)design of the mechanical structure.
Active vibration control is based on the use of sensors, actuators, and electronics, cooperating such that possible errors that may occur within a machine are anticipated or compensated for. Piezo electrical sensors and actuators play an important role in this sense.
Collocated control By combining the actuator and the sensor into a single structural element, it is possible to apply a special kind of feedback control, known as collocated control. In theory, collocated control enables to actively implement the behaviour of a passive mechanical structure. In practice, collocated control is often used to implement robust active damping.