冲量式谷物流量传感器测产信号处理方法  

Signal processing method of impact-based grain flow sensor for predicted yield

作　　者：魏新华[1] 张进敏[1] 但志敏[1] 刘成良[2] 

机构地区：[1]江苏大学现代农业装备与技术教育部重点实验室,镇江212013 [2]上海交通大学机械与动力学院,上海200240

出　　处：《农业工程学报》2014年第15期222-228,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家高技术研究发展计划(863计划)资助项目(2013AA102307);江苏高校优势学科建设工程资助项目(苏财教(2011)8号)

摘　　要：为研究冲量式谷物流量传感器背景振动噪声的提取及剔除方法，以减小背景振动噪声对其测产精度的影响，设计了一套冲量式谷物流量传感器室内标定台架，通过变频调速器控制驱动电机实现输粮搅龙和刮板升运器转速的改变以模拟联合收割机的不同田间工况，并对双板差分冲量式谷物流量传感器的测产信号处理方法进行了研究。通过算术均值滤波初步滤除测量板和参考板输出信号中的随机噪声，通过对参考板滤波输出信号的离散傅里叶变换（discrete Fourier transform, DFT）提取背景噪声的频谱特性，通过测量板和参考板DFT结果的频域差分实现测量板输出信号中背景噪声的剔除，对频域差分结果进行离散傅里叶逆变换（inverse discrete Fourier transform, IDFT）即可得到剔除了背景振动噪声后的传感器输出信号，再对其进行二次算术均值滤波，即得到最终的测产输出信号。通过室内台架标定，建立了谷物籽粒流量与测产输出信号和升运器速度之间的标定模型，并进行了室内模拟测产试验。试验结果表明：谷物流量范围为0.5～2.3 kg/s时，在不同的变频调速器输出频率下，最大测产误差不大于3.1%，测产精度较高且比较稳定，频域差分处理方法能较好地实现双板差分冲量式谷物流量传感器背景振动噪声的剔除。该研究可为冲量式谷物流量传感器测产系统的开发提供参考。Background vibration noise of combine harvester has a significant influence on measuring accuracy of impact-based grain flow sensor. An indoor calibration test bench of impact-based grain flow sensor was developed to study extraction and rejection methods of the background vibration noise from output signal of impact-based grain flow sensor. The test bench was mainly composed of a grain supplying bin, a grain conveying auger, a drag-flight elevator and a grain receiving bin. The auger and the elevator were driven by a three-phase AC asynchronous motor. Grain flow rate was regulated by a spile plate which was mounted at the bottom of the grain supplying bin. Actual grain flow rate was measured with three weight sensors which were mounted between the grain supplying bin and the frame. Revolution speed of the elevator was measured with a revolution speed transducer. Different field working conditions of combine harvester were simulated by adjusting power frequency of the driving motor with a variable frequency generator. A dual-plate differential impact-based grain flow sensor was used in the study which consisted of a measuring plate, a reference plate and 2 strain bridges. The measuring plate accepted impact of the grain flow, and the reference plate sensed background vibration of combine harvester. The measuring plate and the reference plate had a same structure and were parallel mounted to make them have an approximately same mode of vibration. An industrial control system was used to control the variable frequency generator and to acquire output signals of the measuring plate, the reference plate, the weight sensors and the revolution speed transducer. Signal processing was also performed on the industrial control system. Output signals of the measuring plate and the reference plate were acquired synchronously with 3 kHz sampling frequency, and mean filtering was performed to the signals respectively to attenuate random noise. DFT （Discrete Fourier Transformation） was executed to the filtered signals respec

关 键 词：传感器 信号处理 谷物 测产 噪声提取 噪声剔除 频域差分 

分 类 号：S237[农业科学—农业机械化工程]