RTD-A controller : an alternative to PID control?

• Main Author: How, Jacqueline Si Si.
• Other Authors: Vinay Kumar Kariwala
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Chemical engineering::Processes and operations
• Online Access: http://hdl.handle.net/10356/16687
• Institution: Nanyang Technological University

Robustness, setpoint tracking, disturbance rejection and overall aggressiveness (RTD-A) controller has recently been proposed for control of single input single output (SISO) systems. Together with its superior performance, simplicity in implementation and, direct and transparent way of tuning, RTD-A controller seems to be an attractive alternative to widely used proportional-integral-derivative (PID) controller. In order to gain insights, the RTD-A algorithm is analyzed in this project. In particular, a block diagram representation for this controller is proposed. This representation is found to resemble the internal model control (IMC) framework. Using this representation, some guidelines for tuning RTD-A controllers are proposed. It is also proven that the RTD-A controller can be tuned transparently, when the model is the same as the plant but not under significant plant-model mismatch. Furthermore, the available RTD-A control strategy can only be used for processes modeled using first order plus time delay (FOPTD) models. The block diagram representation also facilitates the extension of RTD-A algorithm to other models such as models with integrators. For integrating processes, it is found that the RTD-A controller shows limitations for rejection of load disturbances. In summary, this thesis paves the way for systematic analysis and extensions of a promising control strategy.