The problem of reducing the level of vibration in constructions and structures arises in various branches

of engineering, technology, and industry. In most of today’s mechatronic systems, a number of possible

devices such as reaction or momentum wheels, rotating devices, and electric motors are essential to the

system’s operation and performance. These devices, however, can also be sources of detrimental

vibrations that may significantly influence the mission performance, effectiveness, and accuracy of

operation. Therefore, there is a need for vibration control. Several techniques are utilized either to limit

or alter the vibration response characteristics of such systems. During recent years, there has been

considerable interest in the practical implementation of these vibration-control systems. This chapter

presents the basic theoretical concepts for vibration-control systems design and implementation,

followed by an overview of recent developments and control techniques in this subject. Some related

practical developments in variable structure control (VSC), as well as piezoelectric vibration control of

flexible structures, are also provided, followed by a summary of design steps and procedures for

vibration-control systems. A further treatment of the subject is found in Chapter 7.