In this study, a combine robot was equipped with an autonomous grain container searching function. In order to realize automated grain unloading, the combine robot has to search and identify the grain storage container in an outdoor environment. A planar board was attached to the container. The marker was searched for using a camera mounted on the unloading auger of the combine. An efficient marker searching procedure was proposed on the basis of a numerical analysis of the camera’s field of view and was verified experimentally. The results showed that the combine robot efficiently searched for and detected the marker and positioned its spout at the target point over the container to unload the grain.

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This study proposes a method for detection of uncut crop edges using multiple sensors to provide accurate data for the autonomous guidance systems of head-feeding combine harvesters widely used in the paddy fields of Japan for harvesting rice. The proposed method utilizes navigation sensors, such as a realtime kinematic global positioning system (RTK-GPS), GPS compass, and laser range finder (LRF), to generate a three-dimensional map of the terrain to be harvested at a processing speed of 35 ms and obtain the crop height. Furthermore, it can simultaneously detect the uncut crop edges by RANdom SAmple Consensus (RANSAC). The average of the lateral offset value and crop height of the uncut crop edge detected by the proposed method were 0.154 m and 0.537 m, respectively.

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This research examines the availability of mechanical power and estimates the labor requirements and costs for small-scale rice farming operations in Riau Province, Indonesia. In 2010, we interviewed 120 farmers from the Siak and Kampar Regencies to collect data. We found that farming operations are predominantly performed by human labor because of the lack of farm machines. Between 2001 and 2010, the average availability of mechanical power was just 0.31 hp/ha and this only increased by 0.75% annually. Therefore, annual rice farming operations required 83.26 man-days/ha compared with 7 machine-days/ha. The total cost per hectare for these operations was IDR 7,895,830 (US $877), contributed mostly by labor costs. Farmers should thus adopt more machines to save labor, time, and cost.

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A spread spectrum sound-based positioning system is developed for an open field environment. Errors associated with wind are a major challenge for achieving high positioning accuracy with such a positioning system. Here, wind compensation using a base station configuration is proposed. Field experiments show that by using the proposed compensation method, the influence of wind can be minimized and high positioning accuracy can be achieved. Within a 30 m × 30 m area, the average two-dimensional (2D) positioning accuracy was within approx. 20 mm, at an updating frequency of 2 Hz. Optimization of the base station position was also investigated.

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Thin-layer drying experiments of rough, brown and crushed rice for animal feed were conducted to determine drying characteristics. Since optimization of the drying process reduces cost, we also investigated the conditions for improving the efficiency of rice drying. Rice samples were dried at 40e80 °C with 10%RH. The results showed that 1) the time required for drying crushed rice was shorter than for rough and brown rice, 2) the Page equation was a suitable model to explain the drying characteristics of crushed rice, 3) the drying constant of crushed rice showed the highest value and had Arrhenius-type temperature dependence, 4) the optimum drying temperature of crushed rice was 80 °C.

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