In this paper, a Linear Active Disturbance Rejection Control (LADRC) scheme is presented for the uncertain first order delay time plant. The stable boundary is obtained, which make the tuning process very easy. The controller can be applied to a plant with large time delay. The uncertainty of the system is characterised by the Kharitonov theorem and the gain–phase margin tester approach, combined with the D–partition method, is utilised to determine specific performance boundaries. The analysis is conducted graphically and the feasible regions are explicitly shown in the parameter plane. Numerical simulation is provided to demonstrate the effectiveness of the proposed controller.
Keywords: LADRC, linear active disturbance rejection control, first order delay time plants, stability boundaries, graphical design, gain phase margin tester, controller tuning, uncertainty, numerical simulation