•  
  •  
 

Document Type

Original Study

Keywords

Control Engineering

Abstract

Model uncertainties and exogenous disturbances are inherent phenomena in chemical plants that degrade performance and lead to poor-quality products. To mitigate these Issues, this paper addresses disturbances by exploiting the differential flatness property (DFP) of the nonlinear continuous stirred tank reactor (NCSTR). A two-degree-of-freedom (2DOF) control design was implemented, incorporating flatness-based feedforward and feedforward and feedback controllers. This design leverages the differential flatness method for effective stabilization and tracking performance. A robust feedback tracking control strategy integrating a disturbance observer (DO) and a simple feedback controller was implemented to form a flatness active disturbance rejection control (FADRC) scheme. The B-spline technique was used for trajectory generation to enhance the performance of the proposed control strategy. Additionally, constraints were handled symbolically rather than numerically by designing B-spline curves for the system's flat output. This approach ensures a feasible open-loop reference trajectory that satisfies the feedback controller's states and input constraints. A comparison was conducted between the switching function-based (SF) trajectory and the B-spline (Bs) designed reference trajectory regarding their impact on system tracking performance, smoothness, and robustness to disturbances. A detailed analysis evaluated tracking errors, control effort, and disturbance rejection capabilities under both trajectory designs. The proposed flatness-based ADRC methodology efficiently managed exogenous disturbances and constraints on the input of a nonlinear plant.

Download

Share

COinS