Disturbance rejection–based robust decentralized controller design for a multivariable system

Abstract

A new robust decentralized controller based on a modified linear active disturbance rejection control structure is proposed in this article. In this work, the proposed controller is designed in a two-degree-of-freedom internal model control framework, to overcome the limitations of extended state observer in active disturbance rejection control. In the proposed controller, tuning parameters, that is, observer bandwidth and controller bandwidth are the inverse of the two-time constants, that is, set-point filter and disturbance rejection filter of internal model control (IMC). Moreover, to show the efficacy of the proposed controller, it has been compared with the linear active disturbance rejection controller (ADRC). Furthermore, to exhibit the superiority, an experimentation is conducted on a coupled tank liquid-level multivariable system. From the obtained simulation and experimental results, it is envisaged that the proposed modified linear active decentralized disturbance rejection controller exhibits superior control performance to maintain a precise desired liquid level as compared to the linear ADRC.