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Qiu Q.,National Research Center for Intelligent Agricultural Equipment | Han J.D.,CAS Shenyang Institute of Automation
Science China Information Sciences | Year: 2011

A new real-time algorithm for the autonomous navigation of mobile robots equipped with laser scanners is proposed in this paper. Different from the existing algorithms designed for 2-dimensional navigation problems, the new algorithm introduces the height information of the obstacles into the guidance process and behaves as a 2.5-dimensional angle potential field algorithm (2.5D-APF) to fulfill the navigation requirements under complex outdoor terrain conditions. First, one laser scan is partitioned into two kinds of function sectors: guidance sector and inspecting sector. Then, the guidance sector and the inspecting sectors are reconstructed to form a virtual guidance scan, where the 2.5D information is taken into account. Finally, the conventional APF is improved to analyze the virtual guidance scan and generate the navigation orders. The new algorithm is tested on a tracked mobile robot, and the experimental results validate the proposed algorithm. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg. Source


Gao Y.,National Research Center for Intelligent Agricultural Equipment | Chen T.,National Research Center for Intelligent Agricultural Equipment | Chen L.,National Research Center for Intelligent Agricultural Equipment | Wang Y.,Chinese National Engineering Research Center for Information Technology in Agriculture | And 4 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2010

Aimed at existing problems of duplication, inefficiency in agricultural application software development, the component library technique of agricultural was studied and the agricultural component description model was put forward according to the characteristics of agricultural components. Through analyzing the key problems such as retrieval, release, approval, storage, evaluation and feedback functions in detail, the specific methods of building agricultural component library were given and system of component library that adopts MVC framework was developed. At last, application software development was implemented for experiment and the results showed that component library could effectively improve the quality of software development, and at the same time reduce development costs. Source


Xu G.,China Agricultural University | Xu G.,National Research Center for Intelligent Agricultural Equipment | Wang P.,China Agricultural University | Xue X.,National Research Center for Intelligent Agricultural Equipment | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2014

Drought can lead to yield reduction and is the predominant threat to maize production in China. This study compared responses of different plant types (small plant type CF1002 and large plant type CF3330) to drought stress in a pot experiment of soil water deficit. Three soil moisture treatment included no-stress (CK), mild and severe drought stress. A negative pressure water supply device was used for accurate water supply so as to minimize effect of variation in soil moisture on plant growth and yield. Water use efficiency (WUE), aboveground dry matter, leaf area, and yield and its components of maize were determined. Water consumption at the seedling and silking stages of maize, photosynthetic rate and transpiration rate at filling stage was calculated. The results showed that the WUE of CF1002 increased from 3.24 to 3.43 with increasing drought stress intensity at the seedling stage. In comparison, the WUE for CF3330 decreased from 3.70 to 3.25 under mild and severe drought stress at the seedling stage. Compared with the CK, the WUE of CF1002 and CF3330 was decreased by 2.7% and 24.4% under mild drought stress at the silking stage, and by 17.4% and 57.1% under severe drought stress at the silking stage. The mild and severe drought stress during silking stage decreased the water consumption of CF1002 and CF3330 by 61.3% and 62.5%, the photosynthetic rate of CF1002 and CF3330 by 22.9% and 54.3%, and the aboveground dry matter of CF1002 and CF3330 by 24.8% and 38.0%, thereby resulting in yield reduction by 47.9% and 71.5%, respectively. The decline of water consumption, photosynthetic rate, aboveground dry matter, and yield in CF3330 was higher than that in CF1002. The results above indicated that maize with large plant type (CF3330) was more sensitive to drought stress at the middle-late growth stage such as the silking stage than that of the small plant type. Photosynthesis and transpiration of CF3330 were susceptible to mild and severe drought stress, especially at the silking stage, leading to the reduction of aboveground dry matter production and accumulation as well as water consumption. The difference of CF1002 and CF3330in response of water consumption, yield and water use efficiency to drought stress at the early and late growth stage suggested the necessity of maize cultivation based on plant type. Therefore, optimal water management strategy based on plant type should be applied in the late growth stage after silking in order to reduce damage caused by drought stress. Source

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