• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.22-25
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• 1995

This paper shows adaptive control using RHPC(Receding Horizon Predictive Control) with equality constraint which applied to Electric Furnace. The control strategy includes monotonic weighting (improving transient response) and pre-filtering (enhancing robustness), which is effective on real process. We can observe the performance of RHPC and confirm the practical aspect of RHPC with unmodelled dynamics through the experiment of Electric Furnace. Finally, this paper verifies the feasibility of RHPC to real process.

• 제어로봇시스템학회논문지
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• 제2권1호
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• pp.60-66
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• 1996

Model Based Predictive Control(MBPC) has been widely used in predictive control since 80's. GPC[1] which is the superset of many MBPC strategies a popular method, but GPC has some weakness, such as insufficient stability analysis, non-applicability to internally unstable systems. However, CRHPC[2] proposed in 1991 overcomes the above limitations. So we chose RHPC based on CRHPC for electric furnace control. An electric furnace which has nonlinear properties and large time delay is difficult to control by linear controller because it needs nearly perfect modelling and optimal gain in case of PID. As a result, those controls are very time-consuming. In this paper, we applied RHPC with equality constraint to electric furnace. The reults of experiments also include the case of RHPC with monotonic weighting improving the transient response and including unmodelled dynamics. So, This paper proved the practical aspect of RHPC for real processes.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.27.2-27
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• 2001

This paper proposes a receding horizon predictive control (RHPC) for nonlinear time-delay systems. The control law is obtained by minimizing finite horizon cost with a terminal weighting functional. An inequality condition on the terminal weighting functional is presented, under which the closed-loop stability of RHPC is guaranteed, A special class of nonlinear time-delay systems is introduced and a systematic method to find a terminal weighting functional satisfying the proposed inequality condition is given for these systems. Through a simulation example, it is demonstrated that the proposed RHPC has the guaranteed closed-loop stability for nonlinear time-delay systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.441-445
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• 1997

In this paper, we suggest a design scheme of receding horizon predictive control(RHPC) for boiler-turbine systems whose dynamics are given in nonlinear equations. RHPC is designed for linear state space models which are obtained at a nominal operating point of the boiler-turbine system. In this consideration, the boiler is operated in a sliding pressure mode, in which the reference value of drum pressure is changing according to the electrical power generation. The reference values of the system outputs are prefiltered before they are fed to the RHPC in order to compensate the linearization errors. Simulation results show that the proposed controller provides acceptable performances in both of the cases of 'steep and small changes' and 'slow and large changes' of power demand and yields the effect of modest coordination of conventional PID schemes such as boiler-following and turbine-following control.

• International Journal of Concrete Structures and Materials
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• 제2권1호
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• pp.63-68
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• 2008

High performance concrete (HPC) is widely used in civil engineering due to its high durability and low permeability etc. Compared with ordinary concrete, HPC may develop much higher AS (autogenous shrinkage) at early age due to the relative low water cement (w/c) ratio and adding of mineral admixtures, which is one of the main reasons for early age micro-cracking of HPC structures. This paper studies the early age property of HPC columns under similar construction-site surroundings by embedded strain transducers. Results show that for HPC structure, early-age autogenous shrinkage especially within the first day after concrete pouring is pretty large. AS within the first day are 60% larger than those for 14 days in this research for all specimens. Therefore it should be taken into account for structure durability. By comparison of PHPC (plain HPC column) and RHPC (reinforced HPC column) specimens, the effects of reinforced bars on AS and temperature distribution have been analyzed. Also the influence of w/c ratio on AS is demonstrated.

• 콘크리트학회지
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• 제7권1호
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• pp.126-135
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• 1995

콘크리트의 압축강도는 구조물 설계의 기본요소이며, 압축강도의 증진전개 과정을 통하여 전반적인 시멘트와 콘크리트의 특성을 알 수 있다. 실험결과에 의하면 애쉬(OPC/PFA) 콘크리트는 일반적으로 보통 (OPC)콘크리트보다는 낮은 조기강도를 보여 주었으며 (콘크리트 타설 후 28일 전까지), 그리고 압축강도의 차이점은 콘크리트에 섞은 PFA의 양이 증가할수록 커졌다(애쉬에 의한 시멘트 대체량은 15%, 30% 그리고 45%). 그러나 비록 높은 비율의 애쉬량을 콘크리트에 사용했어도 (대체량 45%) 조기강도 시멘트를 사용한 애쉬( RHPC/PFA 45) 콘크리트의 조기강도는 보통 콘크리트와 비슷한 강도를 보여 주었다. 28일에서 3년까지의 강도실험에서는 애쉬 콘크리트가 포졸라닉(pozzolanic)영향에 의햐여 보통 콘크리트 보다 항상 높은 강도를 보여 주었다. 보통 양생온도 조건보다 높거나 낮은 온도에서는 (5$^{\circ}C$ 그리고 5$0^{\circ}C$) 애쉬 콘크리트가 항상 높은 압축강도를 나타내었다. 그러나 건조 양생시 낮은 양생온도 조건에서는 보통 콘크리트가 더 높은 압축 강도를 나타내었다.