• Journal of Institute of Control, Robotics and Systems
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• v.15 no.7
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• pp.661-666
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• 2009

The linear model following controller(LMFC) scheme controls a plant based on the output of a reference model, thereby replacing a PI controller that has better time response characteristics, which are irrelevant to the structural perturbation of a plant. However, the main weakness of the LMFC scheme is a slow response time to load changes. Thus, to solve this problem, a robust linear model following controller(RMFC) was developed that is robust in load changes. However, when compared with the LMFC scheme, the RMFC scheme has a weaker performance in the case of system parameter changes. Therefore, this paper presents a new LMFC scheme, where the controller is designed based on the output of a plant rather than the output of a model, as in the case of the conventional LMFC scheme. As a result, in the case of load changes, the response characteristics of the proposed scheme are slower than those of the RMFC scheme, yet laster than those of the conventional LMFC scheme, however, for parameter changes, the proposed scheme has a superior performance over the RMFC scheme. The usefulness of the proposed LMFC scheme is verified through a comparison using MATLAB/SIMULINK.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.4
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• pp.411-418
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• 1999

Generally PI controller is used in the servo system, But the time response of the system which is designed by the PI control scheme is deviated from the desired time response by the system parameter variation or the perturbation like the torque disturbance. LMFC(Linear Model Following Controller) is used to make the response of the system follow that of the model even though the parameter variation or the perturbation exists. In this paper, the design method which uses auxiliary model to construct the robustness enhancer in LMFC is proposed. And this robustness enhancer is designed by robust control theory. The proposed method has facter convergence time against low frequency torque disturbance than LMFC. The results are verified by SIMULINK simulation and experiments.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.82-89
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• 1998

PI controller has been used in the servo system. However the time response of the system designed using the PI control scheme does not provide with desirable time response in case of variation in system parameters or perturbation like a torque disturbance. LMFC(Linear model following controller) is being used to make the response of the system follow that of the model even though the parameter variation or the perturbation occurs. In this paper, a design method, RMFC(Robust Model Following Controller) is proposed, which use an auxiliary model in addition to the LMFC, which affords robustness against the low frequency load torque disturbance. The proposed method is more useful to rejecting the low frequency torque disturbance than LMFC. Proposed method is verified by simulation and experiment.

• Computers and Concrete
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• v.26 no.4
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• pp.309-316
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• 2020

The application of multi-variable adaptive regression spline (MARS) in predicting he long-term compressive strength of a concrete with various admixtures has been investigated in this study. The compressive strength of concrete specimens, which were made based on 24 different mix designs using various mineral and chemical admixtures in different curing ages have been obtained. First, The values of fly ash (FA), micro-silica (MS), water-reducing admixture (WRA), coarse and fine aggregates, cement, water, age of samples and compressive strength were defined as inputs to the model, and MARS analysis was used to model the compressive strength of concrete and to evaluate the most important parameters affecting the estimation of compressive strength of the concrete. Next, the proposed equation by the MARS method using particle swarm optimization (PSO) algorithm has been optimized to have more efficient equation from the economical point of view. The proposed model in this study predicted the compressive strength of the concrete with various admixtures with a correlation coefficient of R=0.958 rather than the measured compressive strengths within the laboratory. The final model reduced the production cost and provided compressive strength by reducing the WRA and increasing the FA and curing days, simultaneously. It was also found that due to the use of the liquid membrane-forming compounds (LMFC) for its lower cost than water spraying method (SWM) and also for the longer operating time of the LMFC having positive mechanical effects on the final concrete, the final product had lower cost and better mechanical properties.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.270-273
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• 1996

A scheme of observer-based MFAC(Model Following Acceleration Control) system is proposed for the robustness control of DC servo position control systems. The proposed system is composed of LMFC, variable structure feedback controller, and reduced-order state observer. As the servo motor is controlled by the acceleration command, the total servo system becomes the acceleration control system. Simulation results show that the proposed system have robust properties against parameter variations and external disturbances.

• Journal of the Semiconductor & Display Technology
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• v.7 no.3
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• pp.55-58
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• 2008

The objective of this research is to design, manufacture and test a mass flow controller capable of measuring compressible as well as incompressible fluid flows based on a 'bucket and stop-watch' method. The basic principle behind such a system is the measurement of time, where the time taken to fill and empty a bucket of known volume is measured. This device should be able to handle fluid flows in the range of 0.1 ml/min to 10 ml/min within an accuracy of ${\pm}$1%. For the flow meter to be able to compete with established designs, it must be not only comparable in cost and robustness, but also very accurate and reliable as well.