Experimenting with the Modified Filtered Smith Predictors for FOPDT Plants

Abstract This paper deals with experimental verification of new modified Filtered Smith Predictor with primary 2DOF P-controller that simplifies treatment of the control constraints. Testing the traditional and the new solutions with different disturbance filters by real time experiments on a stable plant fully confirms superiority of the new controllers in constrained control. It also shows that despite to the formal input-to-output equivalence of the new and the traditional solutions, due to different implementation schemes and the plant-model mismatch they give responses to the setpoint and disturbance steps that are slightly different in terms of the speed, monotonicity, as well as noise attenuation. As a by-product of this paper it is shown that both the new and the traditional solutions with the 2 nd order disturbance filter are much more sensitive than those with the 1st order one, what may be crucial for their practical use.

[1]  Ian Postlethwaite,et al.  Multivariable Feedback Control: Analysis and Design , 1996 .

[2]  Adolf Hermann Glattfelder,et al.  Control Systems with Input and Output Constraints , 2003 .

[3]  José Luis Guzmán,et al.  An unified approach for DTC design using interactive tools , 2009 .

[4]  Eduardo F. Camacho,et al.  Dead-time compensators: A survey , 2008 .

[5]  T.H. Lee,et al.  Deadtime compensation via setpoint variation , 2009, 2009 7th Asian Control Conference.

[6]  Julio E. Normey-Rico,et al.  Improving the robustness of dead-time compensating PI controllers , 1997 .

[7]  Eduardo F. Camacho,et al.  Control of dead-time processes , 2007 .

[8]  Jay C. Hsu,et al.  Modern Control Principles and Applications , 1968 .

[9]  Tore Hägglund,et al.  Advanced PID Control , 2005 .

[10]  Tore Hägglund,et al.  Interactive tool for analysis of time-delay systems with dead-time compensators , 2006 .

[11]  Evanghelos Zafiriou,et al.  Robust process control , 1987 .

[12]  Maorui Zhang,et al.  Problem and its solution for actuator saturation of integrating process with dead time. , 2008, ISA transactions.

[13]  Tao Liu,et al.  Analytical design of two-degree-of-freedom control scheme for open-loop unstable processes with time delay , 2005 .

[14]  Eduardo F. Camacho,et al.  Unified approach for robust dead-time compensator design , 2009 .

[15]  O Smith,et al.  CLOSER CONTROL OF LOOPS WITH DEAD TIME , 1957 .

[16]  Antonio Visioli,et al.  Practical PID Control , 2006 .

[17]  Mikulás Huba,et al.  Modular Approach to Teaching PID Control , 2007, IEEE Transactions on Industrial Electronics.

[18]  Wei Xing Zheng,et al.  A double two-degree-of-freedom control scheme for improved control of unstable delay processes , 2005 .