Vibration Suppression and Disturbance Rejection Control of Flexible Systems

柔性系统的振动抑制和干扰抑制是运动控制中的一个重要问题。它起源于轧钢机系统，其中负载通过轴耦合到驱动电机。由于新要求的速度响应非常接近这种系统的主谐振频率，仅仅基于P&I控制的传统技术是不够有效的，为了克服这些问题，已经提出了各种控制策略，主要用于控制2-惯性系统，最简单的模型的柔性系统。本文首先回顾了从简单的模型跟踪控制、状态反馈控制到现代H_∞控制等技术，然后重点讨论了基于扰动消除器的技术，如“谐振比控制”，并通过SIMULINK仿真验证了其优良性能，最后提出了慢谐振比控制。其优点是：（1）干扰观测器的最优速度由显式公式给出。它可以相对缓慢。(2)速度控制器的设计可以独立于振动抑制控制，其实际优良的性能已在由两个电机和若干个可调飞轮通过柔性轴连接而成的特制实验装置上得到了证明。慢共振比控制在频率特性和时间响应波形中给出足够稳定的无振动响应。这是因为控制器中没有快速部件。此外，我们可以使用独立设计的速度控制器的1-惯性系统。这在大多数工业应用中是一个很大的优势。

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.