چکیده (انگلیسی):

Research on Active Vibration Control System (AVCS) is being carried out to reduce structural vibrations
caused by unwanted vibrations in many application areas such as in space, aircraft structures, satellites,
automobiles and civil structures (bridges), particularly at low frequencies. The unwanted vibration may
cause damage to the structure or degradation to the structure’s performance. The AVCS comprises physical
plant, a sensor to detect the source vibration, a DSP based electronic controller using an actuator connected
to the structure generates a counter force that is appropriately out of phase but equal in amplitude to the
source vibration. As a result two equal and opposite forces cancel each other by the principle of super
position and structure stops vibrating. The main objective of this research work is to develop an embedded
computer based real time AVCS for reducing low frequency tonal vibration response of a vibrating flexible
cantilever beam by automatic modification of the vibrating beam’s structural response and to verify the
performance of the developed system experimentally. The developed AVCS is a generic design platform
that can be applied for designing adaptive feed forward AVC and feedback AVC. This study presents the
vibration control methodology adapted for reducing tonal vibration generated by a sine generator connected
to the primary source actuator attached to one end of the cantilever beam. The secondary actuator is
attached to the beam on the other end through the AVCS to reduce primary vibration by destructive
interference with the original response of the system, caused by the primary source of vibration. Adaptive
feed forward Active Vibration Control (AVC) technique is used with Filtered-X Least Mean Square
(FxLMS) algorithm using FIR digital filter. A cantilever beam was considered as plant and embedded
computer based AVCS was tested and evaluated using an experimental setup. The experimental results are
presented for the cantilever beam excited at one of its natural frequency using active vibration control
system and an appreciable reduction was achieved up to 20 dB.