Pericles R. Barros

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In this paper, the auto-tuning of decentralized PID controllers for MIMO processes using different relay feedback experiments is studied. These methods consist in identifying the ultimate point of the process, using relay feedback and applying Ziegler-Nichols-like formulae in order to tune the controllers. A benchmark illustrates the benefits and drawbacks(More)
In this paper the decoupling control of two-inputs two-outputs (TITO) processes using a simplified dynamic decoupler is considered. A frequency-domain identification technique that uses a relay experiment to estimate a first-order plus dead-time (FOPDT) TITO model is presented. The resulting FOPDT TITO model is accurate around at the frequency of interest(More)
— In this paper a proposal for redesign PI controllers with Symmetrical Optimum (SO) based design is presented. The method, introduced by the authors and called Modified Symmetrical Optimum (MSO), uses an integration plus first-order model, identified from two frequency points obtained from combined relay experiment. The proposal for the identification of(More)
In this paper a proposal for redesign PI controllers with Symmetrical Optimum (SO) based design is presented. The method uses an integration plus first-order model, identified from two frequency points obtained from combined relay experiment. The proposal for the identification of the used model is also presented. The main idea is to apply a double(More)
In this paper a methodology is presented to assess the performance of PI controllers from closed-loop response data for pulse setpoint signal. Here a previously published technique is extended to evaluate and redesign single-input single-output (SISO) control loops for single and double pulses. The paper describes a system identification procedure for(More)
In this paper it is proposed a procedure for MIMO closed-loop evaluation and decentralized PI controller redesign using a relay-based experiment in a sequential manner. The experiment data is used to evaluate the actual MIMO closed-loop. It is evaluated using classical robustness measures of each loop. The aim of the controller redesign is to achieve a(More)
Second-Order plus Time-Delay (SOPTD) models are commonly used to approximate systems in order to tune PID controllers. Simple models are dominating for control design in industrial applications. Several estimation techniques have been developed and applied to controller design. Most estimation techniques are based on least-squares and excitations such as(More)
In this work the identification of first-order plus dead-time models from a relay experiment is considered. The relay excitation is applied to the closed-loop. Alternative techniques for identification are examined and simple algorithms are proposed for dealing with the dead-time. Simulation examples are used to illustrate the techniques.
In this paper it is presented a procedure for closed loop controller redesign using a relay based experiment. The present closed loop is evaluated in relation to a symmetrical optimum design. The loop gain is estimated at a few frequency points using an excitation derived from a relay experiment. The controller is redesigned to yield some stability margin(More)