生産資材である農業機械の重要な役割に作業の軽労化, 高効率化, 高精度化がある。この農業機械の究極の姿をロボットに求めた研究開発は国際的にもホットなトピックである。農業機械のロボット化研究はどこまで進んでいるのか?, 実用化する上で何が残された課題か?さらに, ロボットを中核にした農作業技術が実用化した暁には, どのような新たな生産技術が展望できるのか?など, 本稿では車両系農業機械, 特にトラクタのロボット化の現状と将来展望について紹介する。

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We tried to improve the telepresence system to obtain higher efficiency than that offered by the conventional stereoscopic video system, which demonstrated lower efficiency than that under direct viewing and direct operation of the robot. Experimental results indicate that higher efficiency teleoperation requires a telepresence system that satisfies demands for a wide view angle and high spatial and time resolution of cameras and monitors. Furthermore, a higher overlapping ratio of the image of the stereoscopic paired images is effective to improve work performance. Based on experimental results, we developed a stereoscopic image system, named the Q-system, which provides wide angle images with central high spatial resolution images.

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Thermal conductivity of solid silicon as a function of mole fraction of isotope was investigated by molecular dynamics simulation. An empirical potential of Stillinger-Weber potential was used to speculate thermal conductivity of isotope silicon. The equilibrium molecular dynamics based on Green-Kubo's formula was used to investigate thermal conductivity of silicon as a function of mole fraction of isotope. The calculation clarified that thermal conductivity of mixed isotope silicon has a half value of that of pure isotope silicon. The calculation also investigated that pure isotope with light mass has a large thermal conductivity.

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Since smart structures consist of many structural and control components, the possibility of component failures increases due to the complexity and existence of multiple sensors and actuators. This paper investigates model-based failure detection methods for smart structures and proposes a new approach that is insensitive to disturbances due to unknown dynamics and model uncertainties. The present method is applied to a smart structure control system to show the robustness over unknown model errors.

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This article introduces the development of new piezoelectric ceramic devices for smart structural systems, which was carried out at the Institute of Fluid Science, Tohoku University as a part of the smart materials and structural systems research project sponsored by New Energy and Industrial Technology and Development Organization (NEDO). The new piezoelectric devices include high-performance PNN-PZT devices fabricated by a hybrid process of microwave heating and hot-press, PZT and PNN-PZT fibers without metal cores fabricated using a sol gel and powder hybrid process, PNN-PZT fibers with metal cores and functionally graded (FG) PZT bending actuators.

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