Active Vibration Control Technology in China

In the field of engineering, vibration usually leads to structural wear, fatigue, loosening and fracture, which has always been a head-scratching problem to engineers. Researchers introduced a series of solutions to attenuate vibration, such as a physical isolator, damper, or absorber, which later has been named passive vibration control (PVC) technology. The basic idea of PVC is to transfer the vibration energy of the main structure to local/additional structures and finally convert it to heat dissipation. Actually, PVC technology has been widely applied in all fields of engineering. However, with the development of industrialization, the disadvantages of PVC, like poor flexibility, large mass and volume, and limited vibration reduction effect, restrict its application in extreme environments. Under such circumstances, an alternative technology called active vibration control (AVC) has gradually attracted extensive attention. AVC introduces the sensors, actuators and control theory into the vibration control system and reduces or eliminates the unwelcome vibration by adjusting the inherent parameters such as stiffness or damping of the structures dynamically, or directly adding secondary vibration sources to suppress the vibration by superposition principle. Compared with PVC, AVC has the advantages of high flexibility, strong environmental adaptability and good low-frequency control capacity. The prototype of AVC can be traced back to the patent for active noise elimination proposed by German physicist Lueg in the 1930s. In the 1950s, Chinese scientist Hsue-shen Tsien published Engineering Cybernetics [1], a monograph that extended the automatic control theory into practical engineering, which laid the theoretical foundation for AVC. Subsequently, various AVC technologies, e.g., active vibration isolation, active vibration damping, and active vibration absorption, have been widely investigated. Nowadays, AVC has been developed into a multi-disciplinary technology including dynamics, cybernetics, system theory, information theory, and other disciplines.