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Recently, the demand for man–machine cooperative systems has been growing in many industrial fields, particularly in cell production and in flexible manufacturing systems. In the design of man–machine cooperative systems, the characteristics of human behavior must be considered. This paper presents a new design strategy for a switched assist controller for a man–machine cooperative positioning task that takes into consideration a human behavior model based on a continuous/discrete hybrid dynamical system. First, the human behavior model is identified as a piecewise ARX model using k-means clustering and a support vector machine. Second, the switched assist system is designed as a switched impedance controller based on the identified hybrid human behavior model with optimization. The optimization was solved by performing a forward calculation of the closed loop response of the human behavior model and controller with a criterion reflecting the task time and the force effort. The results show that one can find the optimal parameters for a switched impedance controller. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(1): 55–64, 2011; Published online in Wiley Online Library (). DOI 10.1002/eej.20932

▼ This paper describes the development of a parallel-fingered hand with multiple sensing functions for grasping objects with varying hardness, surface roughness, and weight. The multiple sensing functions are: grasping force sensing, static friction coefficient sensing, and weight sensing. Hardware and algorithms are described for measuring the above parameters and for controlling the hand's grasping force by integrating those parameters into a unified control law. We present experimental results that verify the proposed hand system's capabilities of lifting and holding target objects, given only predetermined maximum force settings or limit displacements for the initial grasp. Further studies demonstrate adaptive grasping force control in response to changes in an external force applied to the object, using the static friction coefficient detected by our sensor as a priori information on the object surface roughness.

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Memory capacitors of gallium arsenide pnp structure have been fabricated by use of iron diffusion through n/n⁺/n epitaxial layers. The deep acceptor level of iron was successfully utilized to selectively compensate the lightly doped n-type outer layers. The pnp structure exhibits leakage current comparable to that of a low-leakage GaAs diode. The surface conductance decreases below one tenth after the pnp capacitor is biased at 3 V, which is due to depletion of carriers in the p-type layers. The charge storage time measured by the conductance change was 83 s. Recovery of the conductance by illumination has also been confirmed. © 1998 Scripta Technica. Electron Comm Jpn Pt 2, 80(12): 1–6, 1997

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We have developed a unique induction motor that has free rotating magnets inside its rotor. In experimental results for a prototype motor, we have obtained superior performance over existing motors in terms of the power factor, efficiency, and output torque. The experimental details are as follows. The power factor of the test motor is significantly improved in comparison with that of a conventional induction motor. The power factor can be held to be unity, leading or lagging by changing the line frequency and/or source voltage. This is a quite unique feature, because the power factor of the usual induction motors always lags. The improvement of the power factor is effective not only in decreasing current loss, but also in decreasing voltage drop in the line and increasing installation capacity. The efficiency of the motor is remarkably higher than that of similar-sized conventional induction motors over a wide output power range. Actually, in ordinary induction motors, the efficiency is reduced as the power and/or the source voltage are decreased. However, the proposed motor is driven at high efficiency by lower source voltages in lower power ranges. The efficiency is improved by reducing the secondary current and the magnetizing current. © 1998 Scripta Technica, Electr Eng Jpn, 125(3): 59–66, 1998

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Recently, the demand for man–machine cooperative systems has been growing in many industrial fields, particularly in cell production and in flexible manufacturing systems. In the design of man–machine cooperative systems, the characteristics of human behavior must be considered. This paper presents a new design strategy for a switched assist controller for a man–machine cooperative positioning task that takes into consideration a human behavior model based on a continuous/discrete hybrid dynamical system. First, the human behavior model is identified as a piecewise ARX model using k-means clustering and a support vector machine. Second, the switched assist system is designed as a switched impedance controller based on the identified hybrid human behavior model with optimization. The optimization was solved by performing a forward calculation of the closed loop response of the human behavior model and controller with a criterion reflecting the task time and the force effort. The results show that one can find the optimal parameters for a switched impedance controller. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(1): 55–64, 2011; Published online in Wiley Online Library (). DOI 10.1002/eej.20932