Vibration Suppression and Disturbance Rejection Control of Flexible Systems

点击翻译按钮获取中文摘要

Vibration suppression and disturbance rejection in flexible system is an important issue in motion control. It originates in steel rolling mill system, where the load is coupled to the driving motor by a shaft. As the newly required speed response is very close to the primary resonant frequency of such systems, only the conventional techniques based on P&I control are not effective enough.To overcome the problems, various control strategies have been proposed mainly for controlling 2-inertia system, the simplest model of the flexible system. In this report, firstly, such techniques from very simple techniques, model following controls, state feedback controls and to modern H-infinity controls are reviewd.Next, the discussion was focused into the disturbance observer-based techniques, such as "resonance ratio control", and its excellent performance is shown by simulation using SIMULINK.Finally, the slow resonance ratio control is proposed. Its advantages are as follows :(1) The optimal speed of the disturbance observer is given by an explicit formula. It can by relatively slow.(2) The speed controller can be designed independently of the vibration suppression control.Its actually excellent performance is shown by usinf the specially ordered experimental setup consists of two motors and some adjustable flywheels connected by a flexible shaft. The slow resonance ratio control gives sufficiently stable vibration-less responses in frequency characteristics and time response waveforms. This is because there are no fast parts in the controller. Further, we can use the speed controller independently designed for 1-inertia system. This is a great advantage in most industrial applications.