Conference Paper
Checking if controllers are stabilizing using closedloop data
Res. Sch. of Inf. Sci. & Eng., Australian Nat. Univ., Canberra, ACT
DOI: 10.1109/CDC.2006.377549 Conference: Decision and Control, 2006 45th IEEE Conference on Source: IEEE Xplore

Conference Paper: A control design method for unknown systems using frequency domain data
[Show abstract] [Hide abstract]
ABSTRACT: This paper deals with fixedstructure controller design for stable linear systems by using measurements. Most control design approaches developed in the literature are generally based on a mathematical model which can be obtained via identification system by using a set of measured data. However, an identified model, which is often built on the basis of some assumptions, cannot perfectly describe complex behaviors characterizing physical systems. Thus, the performance expected for the closedloop system will be limited by the quality of such models used in the control design process. Hence, databased controller design methods can be viewed as a possible alternative to modelbased methods. In this paper, we propose to directly utilize frequency response data in the controller design. The principle is to design fixedstructure controllers for which the closedloop frequency response fits a desired frequency response. This problem is formulated as an error minimization problem. The main feature of our proposed approach is that controller can be designed free of any mathematical model, which allows to avoid errors associated with identification process. Moreover, it enables to select loworder controllers, which are suitable for embedded systems. A simulation example is given to illustrate and validate the efficacy the proposed approach.Control Conference (ASCC), 2013 9th Asian; 01/2013  [Show abstract] [Hide abstract]
ABSTRACT: This paper proposes the datadriven performance improvement of lowcost control systems (CSs) for vertical threetank systems. The MIMO CSs dedicated to two tanks of the threetank systems consist of two SISO control loops with separately tuned PI controllers. The Modulus Optimum method is applied to initially tune the PI controllers. Optimization problems are defined on the basis of an original objective function which depends on the controller tuning parameters and is expressed as the sum of squared output errors multiplied by variable weights. The performance improvement is achieved by a new convergent Iterative Feedback Tuning (IFT) algorithm which aims the parameter tuning of PI controllers by the experimentbased solving of the optimization problems. The convergence is ensured by the formulation of the parameter update laws in the IFT algorithm as a nonlinear dynamical feedback system in the parameter space and iteration domain and by setting the step sizes to fulfill inequalitytype convergence conditions derived from Popov's hyperstability theory. The experimental results for a laboratory vertical threetank system show the convincing CS performance improvement by few experiments.Human System Interaction (HSI), 2013 The 6th International Conference on; 01/2013 
Article: A measurementbased approach for designing reducedorder controllers with guaranteed bounded error
[Show abstract] [Hide abstract]
ABSTRACT: The objective of this paper is to present a measurementbased controldesign approach for singleinput singleoutput linear systems with guaranteed bounded error. A wide range of controldesign approaches available in the literature are based on parametric models. These models can be obtained analytically using physical laws or via system identification using a set of measured data. However, due to the complex properties of real systems, an identified model is only an approximation of the plant based on simplifying assumptions. Thus, the controller designed based on a simplified model can seriously degrade the closedloop performance of the system. In this paper, an alternative approach is proposed to develop fixedorder controllers based on measured data without the need for model identification. The proposed control technique is based on computing a suitable set of fixedorder controller parameters for which the closedloop frequency response fits a desired frequency response that meets the desired closedloop performance specifications. The controldesign problem is formulated as a nonlinear programming problem using the concept of bounded error. The main advantages of our proposed approach are: (1) it guarantees that the error between the computed and the desired frequency responses is less than a small value; (2) the difficulty of finding the globally optimal solution in the error minimisation problem is avoided; (3) the controller can be designed without the use of any analytical model to avoid errors associated with the identification process; and (4) loworder controllers can be designed by selecting a fixed loworder controller structure. To experimentally validate and illustrate the efficacy of the proposed approach, proportionalintegral measurementbased controllers are designed for a DC (direct current) servomotor.International Journal of Control 09/2013; 9(9). · 1.14 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.