Sensors 2015, 15, 1496-1517; doi:10.3390/s150101496
sensors
ISSN 1424-8220
www.mdpi.com/journal/sensors
Article
Structure Optimization of a Grain Impact Piezoelectric Sensor
and Its Application for Monitoring Separation Losses on
Tangential-Axial Combine Harvesters
Zhenwei Liang, Yaoming Li *, Zhan Zhao and Lizhang Xu
Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of
Education & Jiangsu Province, Jiangsu University, Zhenjiang, Jiangsu 212013, China;
E-Mails: liangzhenwei518@126.com (Z.L.); zhaozhan@ujs.edu.cn (Z.Z.); justxlz@ujs.edu.cn (L.X.)
* Author to whom correspondence should be addressed; E-Mail: ymli@ujs.edu.cn or
ymli_ujs@126.com; Tel./Fax: +86-511-8879-7338.
Academic Editor: Gonzalo Pajares Martinsanz
Received: 6 November 2014 / Accepted: 30 December 2014 / Published: 14 January 2015
Abstract: Grain separation losses is a key parameter to weigh the performance of combine
harvesters, and also a dominant factor for automatically adjusting their major working
parameters. The traditional separation losses monitoring method mainly rely on manual
efforts, which require a high labor intensity. With recent advancements in sensor
technology, electronics and computational processing power, this paper presents an
indirect method for monitoring grain separation losses in tangential-axial combine
harvesters in real-time. Firstly, we developed a mathematical monitoring model based on
detailed comparative data analysis of different feeding quantities. Then, we developed a
grain impact piezoelectric sensor utilizing a YT-5 piezoelectric ceramic as the sensing
element, and a signal process circuit designed according to differences in voltage
amplitude and rise time of collision signals. To improve the sensor performance,
theoretical analysis was performed from a structural vibration point of view, and the
optimal sensor structural has been selected. Grain collide experiments have shown that the
sensor performance was greatly improved. Finally, we installed the sensor on a
tangential-longitudinal axial combine harvester, and grain separation losses monitoring
experiments were carried out in North China, which results have shown that the monitoring
method was feasible, and the biggest measurement relative error was 4.63% when
harvesting rice.
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