In implementing multivariate statistical process monitoring (MSPM), a frequently encountered problem is the estimation of Confidence Bound, which in fact, is a problem of density function estimation. Traditional assumption of normal distribution of process data often mismatches the real situation. As a new non-parametric method for density estimation, neural network estimator is proposed to estimate the distribution and density function of multivariate statistic. Estimated result is used to calculate the Confidence Bound of multivariate statistical process control (MSPC) chart. Experiment study illustrates the proposed technique has the permit of simplicity and effectiveness.

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The authors previously developed an unconstrained and noninvasive measurement system of heartbeat and respiration using an acoustic sensor enclosed in an air pillow or an air mat. The system measured instantaneous heartbeat and respiration periods by applying Kalman filters and maximum likelihood method respectively to the dynamic models of the heartbeat and respiration signals extracted from the sensor output.
To improve the respiration measurement accuracy especially in a weak respiration case, the paper proposes a measurement system taking into account not only the fundamental mode of the heartbeat, but also the second harmonic component of the heartbeat and the two side band components of the heartbeat made by the respiration.

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This paper proposes a new evaluation method for human multi-joint movements by inspiring human joint-torque characteristics into the manipulability measurements developed for robotic mechanism. A human realizes flexible and skillful movements by controlling his/her musculoskeletal system and the interactive force with environments appropriately. This paper, first, investigates human joint-torque in the lower extremities and reveals its characteristics depending on joint-angle and rotation-direction. Next a quantitative performance index based on human joint-torque characteristics is proposed. The effectiveness of the proposed method is then demonstrated on leg movements in sitting a seat.

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The induction heating inspection is a rather simple and robust system to detect automatically surface flaws of square billets in steels including non-magnetic ones. In this system the induced current goes around crevice cracks in the surface on the rapid RF induction heating and the immediate thermographical mapping reveals flaws as the lower-temperature streaks around the cracks.
The metallic bright scratches marked on conveyers are so low in emmisivity (ε) that they resemble the flaws as the lower-temperature streaks on the map. In order to make the emmisivity uniform all over the surface, authors had applied the spray coating with the resin powder on the billets prior to the induction heating and therewith succeeded in reducing such fake images.
In this paper authors optimized the spray coating with the acrylic resin powder on the square billets in an austenitic stainless steel. The coverage (the coated area/the bare area) increases linearly the emmisivity of the metallic bright surface and 90% is the minimum to equalize it with ε≅1. On the other hand, the coating retards the thermal diffusion through the layer proportionally to its thickness and 20μm is nearly the maximum to avoid the substantial delay in measuring the metal surface temperatures by a radiation thermometer. The highest S/N ratio on the flaw detection is obtained through the coating about 90% in coverage and about 20μm in thickness.

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In Cellular Neural Network (CNN), a design of neighborhood or output function has a great influence on the efficiency of self-recall. In this research, we focused on improving the efficiency of CNN by designing the neighborhood. In CNN which has a local connectivity, it is an important index in improving the efficiency how we design the neighborhood of each cell. In this paper, we proposed a new method of designing the neighborhood, which reduces the recall time while maintaining the classification capability. Next, simulations using model patterns were demonstrated, and it was shown that the proposed method was more effective than the conventional method. Furthermore, we applied the CNN designed by the proposed method to the abnormal sounds diagnosing, and it was shown that the proposed method was also effective in actual application.

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Non-restricted estimate of three-dimensional (3D) walk trajectory during indoor locomotion is discussed. The walk trajectory is derived by the integration of the 3D acceleration of subject's foot. A sensor system is composed of an 3D accelerometer, three gyroscops, and one geomagnetic sensor and is attached on the tiptoe. Integral errors of the acceleration and the angular velocity are modified to keep the continuity of the velocity and the posture of the sensor system between the swing phase and the stance phase. Six subjects performed walk experiments including level walk, ascending, and descending in an office building to verify the proposed method. The experimental results show that the estimation error of 3D location to the actual walk distance is less than 10 [%] and the application of the proposed method improves the precise measurement of 3D walk trajectory.

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With the increasing demand for quick and precise pressure control, measuring the higher response signal (i.e. flux) is required. Formally, in a pressure servo control system, first, pressure in a tank is measured by a pressure sensor, and then, estimation of the flux (as seen in D-PI control systems) or predictive control have been conducted. But if the flux itself can be measured, it contributes to raise the controllability. In this paper, a pressure differentiator applying the principle of isothermal chamber is proposed. Firstly, the principle and the design method of the sensor are discussed. Then, the simulation and experiment are conducted and the results show the effectiveness of the proposed apparatus, and its possibility to future applications.

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This paper deals with development of compliant artificial finger skin surface ridges with a pair of PVDF film strips embedded in each of them as sensing transducers for incipient slip detection in pursuit of elucidating the mechanism of human static friction sensing. We describe design and manufacture of the surface ridges and distinctive detection of incipient slip from rolling.

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This paper considers receding horizon H_∞ control problems using output feedback controllers for generalized linear time varying systems in which orthogonal conditions are not assumed. First, we propose two terminal inequality conditions, which can include the inequality conditions derived in previous results as a special case, for each two riccati differential equations which are needed on output feedback receding horizon H_∞ control problems. The proposed two terminal inequality conditions are important to guarantee stability of the closed loop system. Next, using the proposed terminal inequality conditions, a receding horizon H_∞ controller is proposed. It can be shown that the closed loop system is exponentially stable and L₂ gain of the closed loop system is bounded. Finally, a numerical example illustrates an efficiency of the proposed technique.

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In this paper, we propose a tuning method for PID controllers based on a database-driven function estimation technique. The basic idea of the proposed method is to build a local weighted model from all observed data stored in a database so that a PID parameter meets given design specifications. With several simulations for process control problems, we illustrate the usefulness of the proposed method.

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The purpose of this study is to clarify the temporal structure of speech dynamics in alternate speech. Experimental task is a very simple dialogue in which one speaks “A” and the other speaks “B” alternately. This alternate speech was realized between subject and machine, and subjects should focus their attention to the voice from machine-side. In this condition, two parameters, such as speech duration and speech interval, on machine-side were controlled. This revealed the mutual interaction of speech duration and the mutual interaction of speech interval in alternate speech. Temporal development of speech duration was much faster than that of speech interval in this interaction process, suggesting the temporal hierarchy between them. Furthermore, interaction of speech interval was influenced from breath process and interaction of speech duration was effected from vocalization process. These results suggest that human communication in alternate speech is a kind of hierarchical dynamic process between the control of speech duration and that of speech interval.

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This paper describes the guidance of human being using two vibration motors. A human has the two vibration motors with eccentric weight in both hands. He/she turns right when the motor in the right hand vibrates and the motor in the left hand rests. Similarly, he/she turns left when the motor in the left hand vibrates and the motor in the right hand rests. For showing the effectiveness of the proposed method, the control method of the vibration motors is considered. Firstly, the rotational response of the human from the command signal of the vibration motor is investigated when he/she turns right or left with stamping his/her feet. The results show that the human can follow the rotational command of 1.3Hz. Next, the rotational response with walking is investigated. It is shown that the rotational velocity of the human becomes high when the walking speed is high. Moreover, a peak is observed at 1.3Hz in the frequency response. Finally, the rotational characteristics of the human from the command signal of the vibration motor is modeled as ARX (Auto-Regressive eXogeneous) model and a P controller for making the human turn to a target direction is designed using a root locus. The effectiveness of the control method is shown by simulations and experiments.

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