Aperiodic disturbance rejection in a modified repetitive‐control system with non‐linear uncertainty

• DOI: 10.1049/iet-cta.2016.0479
• Publication Date: 2016-08-24T14:21:25Z
• Authors: Lan Zhou; Jinhua She; Yong He; Chaoyi Li
• Keywords: 0209 industrial biotechnology; 02 engineering and technology

This study deals with the problem of aperiodic‐disturbance rejection for a class of plants with non‐linear state‐dependent uncertainty in a modified repetitive‐control system (MRCS). Since both the non‐linear uncertainty and the disturbances are often unknown, an equivalent‐input‐disturbance (EID) estimator is constructed using a full‐order state observer with variant system matrix to estimate them. The EID estimate, which exhibits the overall effect on the output of the non‐linear uncertainty and all types of disturbances, is incorporated into a linear repetitive control law to compensate for the non‐linear uncertainty and the disturbances. A continuous‐discrete two‐dimensional model of the EID‐based MRCS is built that enables the preferential adjustment of the control and learning actions. A sufficient condition for the robust stability for the EID‐based MRCS is given in terms of a linear matrix inequality. It yields the parameters of the repetitive controller and the EID estimator. Finally, a numerical example demonstrates the design procedures and illustrates the effectiveness of the method.