Second-order System Variable Damping Technology

The damping ratio is an important characteristic parameter in a second-order system, which has great effect on the dynamic characteristic of the second order system. In the second-order system, which has fixed damping ratio, the rapidity and the stability is a contradiction, and can't be gained at the same time. So it can't satisfy with the higher demand of some conditions that require both rapidity and stability.Corresponding to the traditional way, a variable damping control method is an ideal way to improve the dynamic characteristic in the second-order system. Based on the magnitude of the error, which comes from the system's response, it adjust the damping ratio on-line in order to get different damping ratio corresponding different phase of the system response, taking rapidity and stability of the system into consideration at the same time.This paper analyses the effect of the damping ratio on dynamic characteristic in the second-order system. And then, it presents the damping ratio method based on the control of the tachometer feedback. According to adjusting the tachometer feedback channel gain, the damping ratio control is performed. Damping ratio control can be divided into several kinds accompanies with the controlling rules' changing. This paper presents the piece wise linear and nonlinear variable damping ratio approach on the base of analyzing linear damping ratio. Compared with linear damping ratio, it shows better effect in improving system dynamic characteristic.In this paper, when we analyse anti-disturbance performance, according to the feature of the deviation and it's rate of change, which outputted by the system, an anti-interference of the variable damping principle is obtained. By employing the new measurement, the anti-disturbance performance of the second-order obviously improved, and the overshoot also can be effectively restrained.The fuzzy variable damping control approach is introduced in this paper. The application of this method can not only amend dynamic characteristic and improve anti- disturbance performance of the system, but also supply more perfect robust and adaptivity.Matlab is applied to the simulation of a few kinds of variable damping control methods, and the model of simulation system is introduced simultaneously. The simulation results show that adopting variable damping technology in the second-order system, we can remarkably amend dynamic characteristic and improve anti-disturbance performance of the system.