42 research outputs found

    Ultrasonic Doppler Speed Sensor for Agricultural Vehicles: Effects of Pitch Angle and Measurements of Velocity Vector Components

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    High-precision ground speed sensors could be used as a component of navigation or control systems for agricultural vehicles. This paper describes the characteristics of the speed sensor developed by the authors, focusing on the effects of pitch angle. For this purpose, experiments were carried out at various sensor depression angles. The results showed that the output was almost the same as the theoretical value for depression angles of 40 to 50 degrees, although the measurement error was relatively large in the case of artificial turf with short pile. Measurement tests at various angles between the traveling direction and the sensor direction in the horizontal plane were also carried out to determine the possibility of velocity vector measurement including sideslip. It was estimated that the measurement error would be within 3% of the absolute velocity in any direction. The results suggested that it is possible to measure the velocity vector without the effects of pitch angle by using multiple sensors facing in different directions

    Non-destructive technologies for fruit and vegetable size determination - a review

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    Here, we review different methods for non-destructive horticultural produce size determination, focusing on electronic technologies capable of measuring fruit volume. The usefulness of produce size estimation is justified and a comprehensive classification system of the existing electronic techniques to determine dimensional size is proposed. The different systems identified are compared in terms of their versatility, precision and throughput. There is general agreement in considering that online measurement of axes, perimeter and projected area has now been achieved. Nevertheless, rapid and accurate volume determination of irregular-shaped produce, as needed for density sorting, has only become available in the past few years. An important application of density measurement is soluble solids content (SSC) sorting. If the range of SSC in the batch is narrow and a large number of classes are desired, accurate volume determination becomes important. A good alternative for fruit three-dimensional surface reconstruction, from which volume and surface area can be computed, is the combination of height profiles from a range sensor with a two-dimensional object image boundary from a solid-state camera (brightness image) or from the range sensor itself (intensity image). However, one of the most promising technologies in this field is 3-D multispectral scanning, which combines multispectral data with 3-D surface reconstructio

    Shape Recognition and Growth Measurement of Micropropagated Sugarcane Shoots

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    Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a Technical Paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 4 (2002): Y. Kaizu, T. Okamoto and K. Imou. Shape Recognition and Growth Measurement of Micropropagated Sugarcane Shoots. Vol. IV. October 2002

    System for Automatic Separation of Ex Vitro Micropropagated Sugarcane

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    Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a Technical article from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 3 (2001): Y. Kaizu, T. Okamoto and K. Imou. System for Automatic Separation of Ex Vitro Micropropagated Sugarcane. Vol. III, December 2001

    Contact Pressure and Shear Stress Analysis on Conforming Contact Problem

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    Ultrasonic Doppler Sensor for Measuring Vehicle Speed in Forward and Reverse Motions Including Low Speed Motions

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    Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a Technical article from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 3 (2001): K. Imou, M. Ishida, T. Okamoto, Y. Kaizu, A. Sawamura, and N. Sumida. Ultrasonic Doppler Sensor for Measuring Vehicle Speed in Forward and Reverse Motions Including Low Speed Motions. Vol. III, October 2001

    ランキンサイクルによる太陽熱ポンプの研究

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    University of Tokyo (東京大学
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