Reduced Order Based Active Disturbance Rejection Controller Design with Applications

Active disturbance rejection control (ADRC) has emerged as a well-addressed controller design technique in recent years. It is a suitable replacement for the error-based feedback PID controller design approaches. The ADRC constitutes two controller design techniques: linear active disturbance rejection control (LADRC) and generalized active disturbance rejection control (GADRC). The LADRC design approach requires minimal information about the plant, while in the GADRC approach, detailed information about the plant is needed. For higher-order plants, the design of ADRC controllers and extended state observers may be pretty complex and costlier. So, the performance analysis of the higher order plant becomes difficult. Therefore, to make the controller simpler, it is always advantageous to reduce the controller size. This paper proposes reduced order linear active disturbance rejection control (ROLADRC), and reduced order generalized active disturbance rejection control (ROGADRC) techniques instead of full-order LADRC and GADRC approaches. The stability equation method (SEM) and other widespread model order reduction (MOR) methods are utilized to reduce the order of the plant. Further, ROLADRC and ROGADRC are compared with existing control techniques in the literature. The effectiveness of the proposed scheme is tested on the sun tracker system (STS) for position control and power systems for load frequency control (LFC).