Tuning Of Control System Research Articles

Visualization ofN-dimensional performance maps

The performance map has been demonstrated to provide a visual description of dynamical system performance over ranges of parameter value pairs. However, because the effects of only two parameters are visualized, the maps are limited to visualizations in two dimensions. This limits their effectiveness for tuning control systems. In this article, a discussion of the difficulties of three-dimensional performance map generation is provided. Examples are given to illustrate early attempts to generate such a construct and the difficulties encountered. Finally, a novel approach is presented, which will allow the visualization of three and more system parameters. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 801–815, 2006.

Multivariable PID tuning of dynamic ship positioning control systems

This paper introduces the ship dynamic positioning (DP) control problem, details a nonlinear multivariable simulation model for a floating production, storage and offloading (FPSO) vessel and proposes a new model-free linear method for rapid tuning of the DP multivariable PID controllers. Three existing model free tuning methods are compared for their performance and stability properties and a procedure is developed for rapid tuning of DP control systems. Controller structures are discussed and the methods are applied to the simulation model at an operating point, thereby justifying the use of linear tuning techniques. It is shown that some of the methods are appropriate and that it is straightforward to produce a controller of acceptable performance within the thruster input constraints of the ship. Simulation results are presented and analysed. The propose methods are particularly useful for the cases where an adaptive DP control system is required to meet the desired performance.

Implementation and PID tuning of network-based control systems via Profibus polling network

As many sensors and actuators are used in automated systems, various industrial networks are adopted to integrate these components. In order to take advantages of the networking, however, the network implementation should be carefully designed to satisfy real-time requirements considering network delays. This paper presents implementation architecture of a network-based control system via Profibus-DP network and a PID tuning method based on genetic algorithm. Using the implementation architecture, a simple network-based control system is built to control a servo motor over the network. Using this system, the effect of the network delay on the control performance was evaluated, and the controller gains are tuned by genetic algorithm to mitigate the adverse effect of the network delay on the control performance.

A signal convolution method for estimation of controller parameter sensitivity functions for tuning of feedback control systems by an iterative process

Optimisation of controller parameters can be achieved through the use of parameter sensitivity functions in an iterative tuning process. Unlike some other methods for the generation of sensitivity functions, the approach described in this paper avoids the need for explicit a priori knowledge of the plant model structure or parameters, systematic adjustments of controller parameters being made entirely through the processing of signals obtained from tests on the closed-loop system. The methods, based on convolution, may be applied to the estimation of controller parameter sensitivity functions in linear closed-loop systems using simple test inputs, such as step signals. This approach differs from the Iterative Feedback Tuning algorithm in that it does not involve repeated experiments involving system outputs from one test being used as reference inputs in a second test. The signal convolution approach is illustrated through an example involving a simple two-input two-output liquid-level control system involving two coupled tanks.

MATLAB-Toolbox for CAD of Simple Self-Tuning Controllers

The contribution presents a MATLAB-Toolbox for design, simulation and verification of single input single output (SISO) discrete self-tuning controllers. The proposed adaptive controllers who are included into a Toolbox can be divided into two parts. The first part covers PID adaptive algorithms using traditional Ziegler-Nichols method for the setting of the controller parameters, the second part of described controllers is based on the pole placement design. The MATLAB-Toolbox is very successfully used in Adaptive Control Course in education practice for design, simulation and verification of self - tuning control systems in real - time conditions. It is suitable for design and verification of the industrial controllers, too.

MATLAB-Toolbox for Design and Verification of Self-Tuning Controllers

The contribution presents a MATLAB-Toolbox for design, simulation and verification of single input single output (SISO) discrete self-tuning controllers. The proposed adaptive controllers who are included into a Toolbox can be divided into two parts. The first part covers PID adaptive algorithms using traditional methods and pole placement design, the second part is describes controllers based on the minimization of quadratic criterion. The MATLAB-Toolbox is very successfully used in Adaptive Control Course in education practice for design, simulation and verification of self - tuning control systems in real - time conditions.

Tuning and design of single-input, single-output control systems for parametric uncertainty

Frequency domain methods, which are for the design and tuning of control systems for processes with uncertain parameters, and are easy to use and interpret, are proposed. The advantages of the proposed methods over other H∞ methods are mainly that they require substantially less expertise on the part of the designer, and that they result in control system performance that closely approximates that which was desired. Several examples illustrate the proposed methods. A stable second-order lag and dead time process, with gain and dead time uncertainties, provides the vehicle for studying controller designs for single and two degree of freedom control systems. Application of Mp tuning to an uncertain, unstable, first-order lag, plus dead time process, shows that there can be a significant performance penalty associated with using a simple feedback control system rather than an internally stable model-based control system. The performance of a controller for an integrating, oscillatory process obtained by Mp synthesis also compares favorably with that of a controller obtained by other investigators using loop shaping.

Simultaneous online automatic tuning of cascade control for open loop stable processes

In this paper, we present a new simultaneous online automatic tuning method for cascade control using a relay feedback approach. Departing from the traditional approach towards tuning of cascade control systems where the secondary and primary loops are tuned in strict sequence, the proposed approach is to carry out the entire tuning process in one experiment. For ease of practical applications, the entire procedure of controller design may be automated and carried out online. A direct controller tuning approach to tune the controllers is proposed here. Robustness analysis of the new cascade control design is further carried out in the paper by drawing on existing results for SISO feedback systems. Simulations are provided to illustrate the applicability and effectiveness of both the online autotuning approach and the new cascade control design.

Robust on-line relay automatic tuning of PID control systems

In this paper, a robust on-line relay automatic tuning method for PID control systems is developed which expand on the application domain of Astrom's renowned relay autotuning method. In the proposed configuration, a relay is applied to an inner loop of a controller-stabilised process in the usual manner. Using the induced limit cycle oscillations from the closed-loop system, the controller settings may be re-tuned non-iteratively to achieve enhanced performance without disrupting closed-loop control. Two control tuning methodologies are developed – a direct and an indirect method based on an explicit process model. Simulation examples and a real-time experiment are provided to illustrate the practical appeal and potential advantages of the proposed method over the basic one.

Sequential tuning methods of LQ/LQI controllers for multivariable systems and their application to hot strip mills

In this study, we propose such sequential tuning methods of multivariable optimal regulators that can be applied to the tuning of control systems under operation. In such tuning, it is desirable to change feedback gains only step by step, confirming that the control performance is actually improved in each step. The first method we propose is such that we design an optimal single-input regulator in each step, by paying attention to only one input of the plant while the feedback laws to other inputs are fixed to those obtained in the previous sequential tuning steps. On the other hand, the second method is such that all elements of the feedback gain are changed at once, while we are given the design freedom about how much we are to change the gain. These two methods as well as their combined use are shown to lead to the optimal gain as a multivariable control system eventually, provided that the sequential tuning steps are repeated sufficiently many times. We apply these methods to the tuning of LQI servo systems, and carry out the simulation study of the control of a hot strip mill to illustrate the tuning law and show its effectiveness.

Inventory Control in Processes with Recycle

This paper explores one of the important yet unanswered questions associated with the plantwide control of processes with recycle, namely, how inventory control system tuning affects plantwide regulatory performance. The first portion of this paper presents a simple analytic treatment of the problem using simple transfer function models. In the second portion of the paper, a more realistic reactor/column process is studied. Recommendations are given for tuning inventory controllers in a plantwide environment. We show that tight level control of chemical reactors is not desirable from the standpoint of plantwide regulatory control.

Dynamical Complex System. A Parameter Tuning Method for Elevator Group Supervisory Control System By Using Genetic Algorithms.

This paper describesa new parameter tuning method for an elevator group control system. In an elevator group control system tuning parameters describing elevator use and the building environment are important. The new tuning method uses improved genetic algorithms to follow environment changes and to give robustness. Keeping diversity is important in following environment changes. The paper also describes the adding random chromosomes method and adding other estimationsmethod to keep diversity. Their effects are shown by simulations.

Tuning of Gaussian stochastic control systems

A closed-loop system consisting of a control system and an adaptive controller is called tuning for a specified control objective if the real system and the ideal system defined below achieve the same value for the control objective. The real system is the system consisting of the unknown control system in closed loop with the adaptive controller in which the parameters of the adaptive controller have been determined by identification under feedback or in closed loop. The ideal system is the system consisting of the unknown control system in closed loop with a controller in which the controller has been synthesized with knowledge of the unknown control system and such that the closed-loop system satisfies the control objective. Both the Gaussian stochastic control system with full observations and with partial observations are considered. The approach to the problem is based on stochastic realization theory for Gaussian systems. The control objectives of minimum variance control and pole placement are also given. Necessary conditions for tuning are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Automatic Tuning Control of Injection-Locked TEA CO2 Laser.

The automatic tuning control system for the injection-locked TEA CO2 laser was developed. The control algorithm is based on the oscillation delay time (td) which has the minimum value when the cavity is tuned to the frequency of injected beam. The cavity length was adjusted with the speed of 0.9 microns per minute by moving the postion of the rear mirror so that the td is controlled to be minimum value by the computer. As the consequence, more than 97 percent of output laser pulses were maintained to oscillate in single longitudinal mode at repetition rate of 96pps.

Control System Modification in the Taiwan Research Reactor

Because of the discrepancies between design parameters and actual plant data, controller tuning is required during the power testing of a new plant. Furthermore, after a certain period of operation, the effects of aging on the sensors and components cause the system performance to change. With the recent improvements in control system hardware, a better control algorithm can be implemented to ensure the safety of the system. Control system tuning and modification are necessary to keep the system at peak performance. The Taiwan Research Reactor (TRR) is a heavy water-type research reactor. During power operation, a large overshoot in neutron power was observed during a change in thermal power demand. Hence, the dynamic performance of the TRR power regulating system was degraded. From the control system point of view, it is worthwhile to determine the cause of the degraded control system and to tune the corresponding controller setting to achieve better performance. In this paper, the performance of the TRR power regulating system is simulated, the course of the large over-shoot in neutron power is identified, and the control system performance is modified.

Tuning a dynamic positioning system

The tuning of a complex control system used in ships and semisubmersible oil drilling rigs was studied. A method was sought which minimizes the time needed to tune a manned ship. Three different methods were compared to estimate the parameters of the nonlinear state filters used in the control system. Simulations showed that the modified extended Kalman filter did not yield correct parameter values, mainly because the coloured noise originating from the sea waves dominated the estimation residuals. Simple methods based on average propeller forces and ship accelerations were tested by simulation and on a real scale on two ships. An expert system was used for tuning. Experiments showed that the wave forces disturb the acceleration tests too much. Finally, the tuning problem was solved by using the steepest descent optimization method to minimize the square sum of the Kalman filter estimation residuals. Nonlinear optimization seems to be the most promising method for tuning the parameters of the dynamic positioning (DP) system used in off-shore operations. The collection of data over a short period in sea trials followed by tuning of the control system off-line greatly reduces the costs of sea trials. The benefits of expert system techniques were not achieved because heavy signals analysis and optimization computations were required. The tasks where expert systems could be used were so simple that an ordinary high level language was used.

Synthesis of the Overall Boiler-Turbine Control System by Single Loop Auto-Tuning Technique

The synthesis of the control system of the overall hoiler-turbine process represents a non trivial design problem Significant improvements may be achievcd both in terms of efficiency and in terms of plant availaibility, if control functions are well organized. COmplex control systemS architectures may be conceived. but they exhibits the drawback of a comlplex set-up, with often obscure meanings for the plant engineer. So the control system tuning may occupy a relevant portion of the overall plant conmlissioning time. In the paper it is shown that a single-loop auto-tuning tecnique may be successfully adopted for the design of the overall control system. A prototype CAD/CAE enviroment has been developed to support the control design, from scheme editing to software production, with built in tools both for synthesis and for analysis of results General expert rules are obtained and commented

Relay feedback method for tuning of nonlinear pH control systems

For easier implementation of nonlinear pH controllers, we propose an on-line tuning method using the relay feedback with hysteresis. Since just two or three parameters are sufficient to characterize pH processes for practical applications (Williams et al., 1990; Lee et al., 1992), we parameterize pH processes with three parameters and then identify them with the relay feedback testing. The relay feedback method is very popular in on-line tuning of PID controllers (Astrom and Hagglund, 1984; Seborg et al., 1989). This on-line tuning method would reduce the efforts to obtain titration curves with off-line experiments

Tuning of Industrial Control Systems, by A.B. Corripio. Instrument Society of America, North Carolina, USA (1990). 279 pp. ISBN 1‐55617‐233‐8.

Developments in Chemical Engineering and Mineral ProcessingVolume 1, Issue 1 p. 63-64 Book Reviews Tuning of Industrial Control Systems, by A.B. Corripio. Instrument Society of America, North Carolina, USA (1990). 279 pp. ISBN 1-55617-233-8. Martyn S. Ray, Martyn S. RaySearch for more papers by this author Martyn S. Ray, Martyn S. RaySearch for more papers by this author First published: 1993 https://doi.org/10.1002/apj.5500010109AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume1, Issue11993Pages 63-64 RelatedInformation

Numerical optimization for self-tuning electrohydraulic control systems

In this paper we present an approach to self tuning control system for hydraulic actuators with flexible mechanical loads. Explicit criteria optimization using the COMPLEX optimization algorithm is used to adjust the regulator parameters towards their optimal values.The regulator structure is obtained by considering the problem in a linear state space formulation and by computing a regulator based on state feedback and state estimation. Results from experiments carried out on a lorry crane are presented.