This paper provides a closed-loop identification method based on generalized minimum variance (GMV) evaluation. The method assumes that the system model is represented as the CARMA (Controlled Auto-Regressive and Moving Average) model, and identifies parameters of a disturbance model as well as plant parameters. Closed-loop input and output measurements on the nominal GMV controll system are used for the identification. The present method has a distinctive point in terms of using the data-driven control specification for minimizing the variance of the generalized output. The paper proves that minimization of the proposed cost function results in identifying plant and disturbance model parameters uniquely. Finally, the effectiveness of the proposed method is demonstrated through numerical examples for both stable and unstable processes.

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The recent regulations for engine emissions require precise temperature control. Because high response temperature measurement is difficult, engine torque, which is closely correlated with the temperature, must be estimated. We propose a method for estimating engine torque from the crankshaft rotation speed. This method consists of four steps, (1) the measured engine speed ω is analyzed and divided into frequency components, (2) each component is multiplied by the gain, which is proportional to the frequency, (3) the phase of each component is shifted by 2π/4, (4) the combustion torque is estimated by synthesizing each component. These steps are summarized into one filter. The output of the filter is compensated for by the geometrical character of the engine link mechanism. The method was evaluated through experimentation. In the steady and transient states and under the condition that the engine speed was not greater than 1000rpm, the estimated torque accurately follows the reference torque. However, when the engine speed increases to 2000rpm, the pulsation in the estimated torque becomes noticeable. Based on the estimated torque, IMEP (Indicated Mean Effective Pressure) was estimated within an accuracy of 3.4% when the engine speed was not greater than 1000rpm. When the valve timing changed, the estimated IMEP followed the change in reference IMEP.

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A robust model predictive controller design is proposed in view of application to photovoltaic battery charge/discharge operation. The purpose of the battery operation is to recover the battery charge to a desired periodic level while keeping the proper operating ranges. We achieve the periodic constraint satisfaction under power demand forecast errors by extending the time-invariant constraint tightening technique. The calculation of the model predictive control law can be completed before beginning the battery operation. An advantage of the offline implementation is illustrated by assessing the relationship between the spinning reserve and recoverable battery charge region.

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This paper proposed a novel objective pain intensity assessment technique using the change of peripheral arterial stiffness β, which reacts to a peripheral sympathetic nervous activity. The stiffness β is calculated from continuous arterial pressures and photo-plethysmograms beat-by-beat based on the log-linearized peripheral arterial model. In the experiment, the validity of the proposed method was examined by comparing estimated normalized arterial stiffness β_n with simultaneously-measured numeric rating scale (NRS) as a general index of pain intensity when electrocutaneous stimuli were applied to the healthy subjects. The results showed the maximum amplitude of electrocutaneous current I_max has linear correlation with the normalized stiffness β_n (R² =0.77, p < 0.05). In addition, both the maximum amplitude of electrocutaneous current I_max and the normalized stiffness β_n strongly correlated with NRS values by sigmoidal curves (I_max v.s. NRS: R² =0.91, p < 0.01; β_n v.s. NRS: R² =0.92, p < 0.01). It was therefore concluded that the proposed method can assess pain intensity objectively.

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We propose a novel optimal sensor placement determination method for jet engines. In jet engine health monitoring, fault detection with a state estimation is frequently carried out. A straightforward approach to obtain accurate estimations is to directly observe all the physical quantities of interest. However, typically, only a subset of them is observable. Moreover, in practice, the number of sensors is often limited due to cost and weight. Therefore, optimizing sensor placement is an important problem. More specifically, we solve a problem to maximize the estimation accuracy by optimally choosing a given number of physical quantities that are measured by sensors. We validate the proposed method by extensive simulations.

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A digital halftoning method for DLP projector system is proposed in this paper. PWM type 2-value images have been rapidly switched to achieve high resolution image in DLP projector systems. To achieve high frame rate image projection with high image quality, it is required to reduce the number of 2-value images with small degradation of the image quality. We propose a framework for optimizing color quantization and luminance for DLP projector system with a few number of the 2-value images. The optimal light intense is designed based on a particle swarm optimization algorithm. We illustrate the effectiveness of the proposed method by numerical examples.

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This study aims at proposing a novel concept of a secured controller to achieve enhancement of cyber-security in networked control systems using RSA public-key encryption. With homomorphism of the RSA encryption, the proposed method enables to conceal not only signals over communication links in the control systems, but also parameters of controllers used in determining a control input. A numerical example is employed to confirm that the proposed method correctly functions for the cyber-security enhancement.

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This study proposes how to encrypt controllers using ElGamal encryption system. Based on a homomorphism of the ElGamal encryption, the proposed method enables to conceal not only signals over communication links in the control systems, but also parameters of controllers used in calculating a control input. A numerical example confirms that the proposed method correctly works for the cyber-security enhancement.

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