This paper proposes a method of controlling the tracking errors attributable to current based on a Heading Control System (HCS) which focuses on the aspects controlled by the heading of a Track Control System (TCS) and the aspects comprised in the straight and circular-leg segments of the planned route. The HCS is comprised of a reference heading and a 2-degree-of-freedom control (2DOFC) system to provide course keeping and course changing functions. The proposed method pertains to a tracking control loop for both the straight-leg and circular-leg segments of the route and involves separating the TCS into the HCS control loop and the tracking control loop and adopting a reference route derived from the reference heading and ship speed. In the straight-leg segments of the route, constant current components are estimated based on the tracking errors from the reference route and these current component estimates are used to correct side slip angle through feed back control. In the circular-leg segments of the route, the current component estimates are used to correct side slip angle and the turn rate through the reference heading and 2DOFC. As the ship's heading follows the reference heading by means of the feed forward control operation, the side slip angle cancels the current component of the route's normal direction. The rate of turn relates to changes in ground speed (sum of current and ship speed) to maintain a constant radius. Additionally, reach is estimated from the reference heading and the feed forward control. Reach refers to the distance from the start position of the circular-leg. The validity of this proposed method was verified by simulation results.

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The new air-conditioning control technology for the energy saving for buildings is proposed. The method is mainly focused on the compatibility of energy savings and comfort. The energy saving is achieved through the next generation air handling unit that controls room humidity without energy loss and the optimal operation of HVAC (Heating, Ventilating and air-conditioning) system, manipulating the supplying airflow temperature to the rooms, room temperature and the humidity. The comfort is kept by the index (PMV: Predicted Mean Vote) that calculated with room temperature, humidity, radiation temperature, wind velocity and so on. In order to find the HVAC system operation conditions that satisfy the comfort and energy saving at the same time, very large-scale nonlinear programming with nonlinear constraints must be solved on real time basis. To make the programming of the system practical, the driving function loaded onto a control computer is introduced. The function is made by the spline interpolation to achieve calculation stable and to adapt to various HVAC operation modes. The effectiveness of the HVAC control technology is proved through a building HVAC data and the simulations using the data.

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Demand among large office buildings for the energy-saving benefits of the HVAC (Heating, Ventilating and Air-Conditioning) System are increasing as more and more people become concerned with global environmental issues. However, immoderate measures taken in the interest of energy conservation may encroach on the thermal comfort and productivity level of office workers. Building management should satisfy both indoor thermal comfort and energy conservation while adapting to the many regulatory, social, climate, and other changes that occur during the lifespan of the building. This paper demonstrates how optimal control of the HVAC system, based on data modeling and the multi-objective optimal method, achieves an efficient equilibrium between thermal comfort and energy conservation.

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Model predictive control has been widely used in industrial applications. And more efficient and more precise control is being required to meet growing demands such as energy savings and fewer emissions in industrial plants. In this paper, we focus on step response model based predictive control, which is one of most applied predictive control methods, and propose a new disturbance rejection method to overcome control performance degradation caused by unmeasured ramp-like disturbances.

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Research has been conducted on a variety of combustion technologies in order to reduce diesel engine emissions. These technologies should precisely control the state of in-cylinder gas (EGR mass flow, air mass flow, and so on). However, because the controlled object is a multi-input, multi-output (MIMO) system and a coupled system, the use of control systems based on the conventional methods that employ PID controllers represents a challenge. Model predictive control (MPC) is well known as an MIMO algorithm. An intake control system that could be applied to the intake system of a diesel engine was constructed by supplementing MPC with a feedback function using a disturbance observer and compensator for the nonlinear characteristic of the actuators. Performance tests using an actual vehicle verified that, when applied to a two-input (throttle valve and EGR valve), two-output (air mass flow and intake chamber pressure) system, the proposed MPC is able to rapidly control each output independently to the target value.

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In the hot strip mill, the quality of the strip greatly depends on the cooling process between the last stand in the finishing mill and the coilers. Therefore, it is important to carefully control the coiling temperature to regulate the mechanical properties of the strip. To realize high accuracy of coiling temperature, a new coiling temperature control using temperature measurement method for the hot rolled strip in the water cooling banks has been developed. The features of the new coiling temperature control are as follows: (i) New feedforward control adjusts ON/OFF swiching of cooling headers according to the strip temperature measured in the water cooling banks. (ii) New feedforward control is achieved by dynamic control function. This coiling temperature control has been in operation successfully since 2008 at Kashima Steel Works and improved the accuracy of coiling temperature of high strength steel considerably.

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A technique for performing parameter identification in a locally weighted regression model using foresight information on the physical properties of the object of interest as constraints was proposed. This method was applied to plan view pattern control of steel plates, and a reduction of shape nonconformity (crop) at the plate head end was confirmed by computer simulation based on real operation data.

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This paper considers the NCSs (Networked Control Systems) by PID controller. We discuss the packet losses, especially, the improvement of the response degradation caused by the MV (Manipulated Variable) packet losses. When MV packet is lost, the actuator complements the MV by some value, which is input to the plant. This complemented value is different from the MV calculated by the controller. This makes the internal state of the PID controller such as integral value inappropriate, and it degrades the response. We propose the compensation method which corrects the internal state of the PID controller. When the actual values of MV are obtained after the MV has been lost by packet loss, the value of SV (Set point Variable) at the sampling time point on which MV has been lost is modified such that the actual MV is calculated using the PV (Process Variable) and the modified SV. Moreover, we propose the MV complement method that modifies the method which holds the last available MV. And we demonstrate the effectiveness of these methods by simulation studies.

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In this paper, the pitch angle control design problem of wind turbine generator is considered. Dynamic characteristics of wind turbine system vary according to the wind speed and also the generator speed. But it is required to maintain the generator speed at the optimal one in spite of such variations. For this purpose, the pitch angle control of wind turbine which includes the robust stability is used. However, the conventional standard H_∞ control provides conservative performance, so the control performance is inferior to conventional controllers such as gain scheduling PI controls. In this paper, a result of a pitch angle control of wind turbine generator by using the less conservative robust control is shown. Obtained control performances are verified based on the dynamic simulator “Bladed” and it is confirmed that the obtained controller provides acceptable control performances by a fixed parameter controller. And the performances are almost the same as the results by the gain scheduling PI control.

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This paper presents a model-based design method of modulators included in DC/AC inverters. The proposed method is based on parameter-dependent linear matrix inequalities, which can give modulators for robust and efficient inverters. It is shown by numerical examples that the resulting inverter has higher performance than that with the typical pulse width modulator.

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This paper discusses the dynamic games for a class of discrete time weakly coupled large-scale stochastic systems. First, it is shown that Pareto and Nash strategy set can be designed by solving the cross-coupled stochastic discrete algebraic Riccati equations (CSDAREs). After establishing the asymptotic structure for these solutions of CSDAREs, weak coupling parameter independent strategy sets are given for their problems respectively. It is shown for the first time that these parameter-independent strategy sets are the same and the proposed strategy sets attain the Pareto suboptimarity and the approximate Nash equilibrium. In fact, it is proved that these strategy sets achieve O(ε²) approximation for all cost performances. Furthermore, it is worth pointing out that the proposed approximate strategy sets can be constructed by solving the parameter independent reduced-order discrete algebraic Riccati equations (DAREs) via LMI. As a result, the suboptimality of overall cost for each subsystem can be attained. Finally, in order to demonstrate the efficiency of the proposed design method, a numerical example is provided.

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Recently, MOESP-type closed-loop subspace model identification (CL-MOESP) has been proposed by the authors and its effectiveness has been demonstrated via both numerical simulations and real-life systems, e.g., a cart-inverted pendulum system. However, asymptotic properties of CL-MOESP has not yet been studied. The purpose of this paper is to clarify the asymptotic properties of CL-MOESP from the viewpoint of Two-stage closed-loop identification. Moreover, it is shown that CL-MOESP minimizes a truncation error due to a finite number of sampled data.

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This paper describes a VCO (Voltage Controlled Oscillator) by ceramic resonator with variable reactance circuit using positive/negative capacitance circuit. Because ceramic resonator is made of stable piezoelectric ceramics and its oscillation frequency is primarily adjusted by the size and thickness of the ceramic element, a ceramic resonator has high oscillation and Q stabilities. Ceramic resonator is frequently used as VCO by adding external variable capacitance circuit. But external capacitance gives a negative effect that an oscillation frequency should go down lower than physical fixed value. The variable reactance circuit realized by positive and negative capacitance circuit can make the oscillation frequency either decrease or increase. Additionally, when a reactance circuit is balanced on neither positive nor negative, the ceramic resonator's oscillation frequency is equal to physical fixed value unaffected by reactance circuit. We designed the oscillation circuit and variable reactance circuit suitable for LSI, and we built this VCO with reactance circuit onto PLL system for evaluation.

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