A Design Method of Dual-Filter Disturbance Observer for Non-Minimum Phase Systems

Abstract

The invention discloses a double-filter disturbance observer design method for a non-minimum phase system, which is used to solve the problem that the traditional disturbance observer method is unstable in the non-minimum phase system and cannot suppress disturbance. The present invention introduces a forward model, and provides a new disturbance observer frame structure and a double filter design scheme. The invention starts from the frame structure of the new disturbance observer, carries out stability constraints on the double filter, and analyzes the tracking characteristics and disturbance suppression characteristics of the system under the premise of ensuring the stability of the system. The filter one in the present invention adopts the design of the original closed-loop controller, and the filter two is designed according to the filter one, and realizes the same performance as the filter one. On the basis of not changing the tracking characteristics and stability of the closed-loop non-minimum phase system, the invention can use any filter alone to double the disturbance suppression capability of the system, and use dual filters at the same time to improve the disturbance suppression capability of the system. twice as high.

Description

technical field [0001] The invention belongs to the field of control systems, and in particular relates to a method for designing a double-filter disturbance observer for a non-minimum phase system, which is mainly used for improving the disturbance suppression capability of a closed-loop non-minimum phase system without changing the tracking characteristics and stability. . Background technique [0002] In the control system, in addition to the common minimum phase system, there are also non-minimum phase systems that are inherently stable but contain non-minimum phase links, such as lag systems, grinding circuit systems and DC motors. Non-minimum phase systems are difficult to control due to the fundamental limitation of non-minimum phase elements in their control performance. The disturbance suppression characteristic of the closed-loop non-minimum phase system is limited to the single closed-loop system itself, and the disturbance suppression capability is insufficient....

AI Technical Summary

Problems solved by technology

According to the document "A New DisturbanceObserver for Non-minimum Phase Linear Systems", when the traditional disturbance observer method is used in a non-minimum phase system, since the inverse model is indispensable, it will lead to unstable poles in the system, making the system unstable. Lose the disturbance suppression effect, and even cause system crash

In this paper, a disturbance observer method for non-minimum phase systems is also proposed, but the method is modified for non-minimum phase objects, which will inevitably affect the original tracking characteristics and stability of closed-loop non-minimum phase systems

In the document "An approximate inverse system for nonminimum-phase systems and its application to disturbance observer", the proposed disturbance observer is limited to the estimation of disturbance without considering the stability of the closed-loop system, which has great limitations

Images