Controlling self-excited vibration using positive position feedback with time-delay

Abstract

This paper explores the vibration control of Rayleigh oscillator (a self-excited system), by using positive position feedback method. Both linear and nonlinear stability analyses are performed. The stability regions and optimal system parameters are obtained by performing linear stability analysis, and nonlinear analysis is performed using describing function method to get the amplitude and frequency of the system. The effect of time-delay on system performance is also studied in this paper. It is observed that the existence of time-delay can be unfavourable; however, the situation can be improved by increasing the loop gain. However, it is impossible to design a system without time-delay present in the feedback circuit. Therefore, to nullify the effect of uncertain time-delay, authors have intentionally introduced a preselected time-delay in the feedback circuit and re-optimized to stabilize the static equilibrium of the delayed system. Numerical simulations performed in MATLAB SIMULINK confirm the results of the theoretical analysis obtained.