Active Vibration Absorber with Curved Beam Design

Abstract

The project aims to design and create an active vibration absorber with a curved beam to reduce vibration. The selected frequency of the vibration generator for this research was limited to 10 to 30 revolutions per minute and is forced to move in one dimension. The vibration generator was controlled by variable resistance with an unbalanced mass that produces centrifugal forces between 14.799 and 133.189 newtons at frequencies of 10 and 30 revolutions per minute, respectively. To control the natural frequency of the active vibration absorber, the microcontroller STM32F103C8T6 - Black Pill and absorption frequency was used with a set of controlling criteria that help to adjust a spring's stiffness. The spring was designed as a curve beam so that the absorber would be small and easy to use while having a wider working range and reacting quicker to a change in load. To reduce system vibration, the spring stiffness was properly adjusted by changing the curve beam's length by changing the locker arm's position using a rotating motor. The feedback control system, meanwhile, was used to adjust the motor's position through variable resistance and then calculate a feedback error to the corrected position, resulting in a natural frequency of the absorber that was similar to the system's vibration frequency. Moreover, the relationship between spring stiffness and curve beam length was also investigated to obtain the function of locker arm position and specify the angle of the motor's shaft. Experiments to test the correctness of theory and method were also conducted. Prior to the experiment, the vibration absorber's efficiency was assessed using ADAMS motion simulation software. The efficiency as a percentage drop in the main system vibration amplitude was calculated while the vibration absorber was mounted. At an operating frequency of 15 Hz, which is close to the natural frequency of the main system, the test results show that the vibration can be reduced by up to 65.49 percent. However, based on the experiment's results, the efficiency was defined as a percentage of a reduction in vibration amplitude in the primary system, both with and without an active absorber. The most efficiency as a percentage drop in the main system vibration amplitude was 34.917%, while the least efficient was 7.711%. It was concluded that the active vibration absorber design with the curved beam can reduce vibration, and while the results were not the best, they were enough to warrant the commencement of future studies.