、课题
Vibration Control
In recent years, many engineering systems are becoming increasingly complex, making them difficult to accurately control. Vibration control is an integral component of many control systems, particularly when servo control or stabilization is required. Any system with mechanical components and dynamic behavior must be controlled so as to maintain stability and reduce vibration arising from external and internal forces. Indeed, vibration control is fundamental in many engineering fields, from machine tools and robotics to aerospace applications, and from the design and construction of larger integrated structures to the servo-control of loudspeaker systems. In each case, the effective control of vibration requires an understanding of the system in all its complexity, including, for example, its representation in mathematical form, its mechanical and electrical components, any feedback loops, and the choice of appropriate control strategies.
The ability to accurately identify vibration sources is an important prerequisite to any successful vibration control system, since the precise source of undesired vibration must be identified before a control strategy can be formulated. Knowledge of the type and magnitude of the vibration usually helps to identify the source and possibly its degree of severity. Identification of the source can be accomplished using several techniques, such as using feedback signals, testing components, and measuring dynamic behavior. Once the source of vibration has been correctly identified, a suitable control system can be designed to reduce or eliminate the vibration itself.
The most common type of vibration control for mechanical applications is direct-force cancellation. This type of control works by applying a force to the system which is opposite in direction to the magnitude of the unwanted vibration forces in order to cancel them out. This is best used when the sources of vibration can be accurately determined, as the control must be tuned specifically to those sources in order to be effective. For example, the vibration of a table saw blade can be cancelled out by applying an opposing force to the saw blade, through a bearing system.
Another common method of vibration control is feedback control. As its name implies, this technique uses feedback as a means of controlling the system’s dynamics. That is, the feedback signal is used to actively modify the system dynamics to maintain the desired state. This can be accomplished through a combination of damping, gain adjustment, and disturbance rejection. Feedback control is generally used where the vibration source is unknown or changing, and it is stable enough that larger disturbances can be rejected.
In addition to direct-force cancellation and feedback control, there are several other methods of vibration control, such as external and internal damping, modal control, and active vibration control. External and internal damping involve the use of springs, mass dampers, and other mechanical means of reducing vibration. Modal control works by selectively modifying the dynamics of the system to reduce the magnitude of natural frequencies within the structure, and active vibration control uses control strategies to identify and actively reduce vibration.
Vibration control is essential for many different types of engineering systems. It is critical for maintaining system stability and for providing high levels of accuracy and precision in operation. The field of vibration control is complex and multidisciplinary, and involves a wide range of techniques and strategies to achieve the desired outcome. There is no single method of vibration control that is suitable for all applications, and so it is important to carefully consider the system requirements in order to ensure the most effective solution is applied.
