A novel grain flow sensor consists of an impact plate and a PVDF(Polyvinylidene Fluoride)piezoelectric film was developed in this research.The kinetic model of the grain flow sensor was built to analyze the steady and...A novel grain flow sensor consists of an impact plate and a PVDF(Polyvinylidene Fluoride)piezoelectric film was developed in this research.The kinetic model of the grain flow sensor was built to analyze the steady and transient vibration disturbances which had a significant influence on performance of the sensor,and the results showed that damping ratio of the sensor was the key factor to improve accuracy of the sensor.To maximize damping ratio of the sensor,the thickness of the impact plate and damping material were optimized according to a loss factor model of the free damping structure.The optimized results indicated the most appropriate thickness ratio of damping material and the impact plate was 6.A test rig equipped with the novel grain flow sensor and weight sensors which could simulate field situations was built to investigate the performance of the sensor,on which test experiments under different feed flows were conducted.The results showed that the maximum error of the sensor was 3.02%and the mean error was 2.15%,which revealed that the novel grain flow sensor could be used to measure grain flow.Comparing with conventional grain flow sensors,the novel grain flow sensor has the features of high accuracy,simple structure and flexible signal processing methods.展开更多
The grain yield data collected by the intelligent yield measurement system of the combine harvester is generated into a field plot yield distribution map,which is of great significance for guiding agricultural product...The grain yield data collected by the intelligent yield measurement system of the combine harvester is generated into a field plot yield distribution map,which is of great significance for guiding agricultural production.However,in the process of drawing the yield map,the combine harvester is affected by vibration during operation and the generated error data in the process of collecting data which will cause the drawing results to be inaccurate.This study researched two factors that cause errors,then,the influence of vibration interference on the measurement signal was eliminated by filtering,vibration isolation,and designing a double-plates differential grain flow sensor.Three methods were taken to eliminate random errors,gross errors and systematic errors,including using the arithmetic average value to replace the true value,the 3σcriterion,and removing the filling time data and the delaying time data.Finally,the grain yield distribution map was obtained through Matlab and Excel.The results showed that the interference frequency above 50 Hz could be eliminated by filtering,but it was difficult to filter the low-frequency signal which was close to the grain impact frequency.The vibration amplitude was reduced to 14.29%by adding a vibration isolation plate,and the SNR was increased from−4.67 dB to 29.21 dB by combining low-pass filtering and damping vibration isolation.When the grain feeding rate was 2 kg/s,the natural vibration amplitude of the sensor after difference was about 0.02 V and evenly distributed around the zero voltage 0.2 V.The influence of positive and negative offset on the average value of grain impact signal could be ignored,and the signal-to-noise ratio was increased from 29.21 dB to 62.49 dB.The results of field experiments showed that the yield map drawn can clearly display the yield value of the harvest area,which is used to guide agricultural production.展开更多
为减少联合收获机振动对谷物流量传感器监测结果的干扰,设计了一种基于声学黑洞(ABH,acoustic black hole)原理的谷物流量传感器龙门支架减振结构,通过有限元方法分析减振结构的振动特性,分析了二维声学黑洞比例系数ε、幂函数指数m和半...为减少联合收获机振动对谷物流量传感器监测结果的干扰,设计了一种基于声学黑洞(ABH,acoustic black hole)原理的谷物流量传感器龙门支架减振结构,通过有限元方法分析减振结构的振动特性,分析了二维声学黑洞比例系数ε、幂函数指数m和半径R对其减振性能的影响规律。结果表明,声学黑洞能够显著降低龙门支架的振动,ε、m和R对声学黑洞减振性能的影响均未表现出明显线性关系,当ε=0.001 2、m=2.5、R=15 mm时声学黑洞的减振效果最好。以振动速度平方和作为优化目标,建立了多项式回归代理模型,通过遗传算法对声学黑洞比例系数ε、幂函数指数m和半径R的取值进行了优化。相比于未添加声学黑洞的原始龙门支架和初始声学黑洞方案,优化后龙门支架的振动速度平方和分别降低68.92%和2%,表明优化方案具有更佳的减振性能。提出的基于声学黑洞的减振结构和优化设计方法为农业机械被动宽频减振研究提供了理论参考。展开更多
基金the Key Technologies R&D Program of Liaoning Province(Y5L7160701)National High-tech R&D Program of China(863Program)(2013AA040403).
文摘A novel grain flow sensor consists of an impact plate and a PVDF(Polyvinylidene Fluoride)piezoelectric film was developed in this research.The kinetic model of the grain flow sensor was built to analyze the steady and transient vibration disturbances which had a significant influence on performance of the sensor,and the results showed that damping ratio of the sensor was the key factor to improve accuracy of the sensor.To maximize damping ratio of the sensor,the thickness of the impact plate and damping material were optimized according to a loss factor model of the free damping structure.The optimized results indicated the most appropriate thickness ratio of damping material and the impact plate was 6.A test rig equipped with the novel grain flow sensor and weight sensors which could simulate field situations was built to investigate the performance of the sensor,on which test experiments under different feed flows were conducted.The results showed that the maximum error of the sensor was 3.02%and the mean error was 2.15%,which revealed that the novel grain flow sensor could be used to measure grain flow.Comparing with conventional grain flow sensors,the novel grain flow sensor has the features of high accuracy,simple structure and flexible signal processing methods.
基金supported by the Open Project of the Key Laboratory of Modern Agricultural Equipment and TechnologyMinistry of Education of the PRC(Grant No.JNZ201911)the Youth Talent Development and Program of Jiangsu University,and the Key Laboratory of Agricultural Equipment and Intelligent High Technology Research of Jiangsu Province.
文摘The grain yield data collected by the intelligent yield measurement system of the combine harvester is generated into a field plot yield distribution map,which is of great significance for guiding agricultural production.However,in the process of drawing the yield map,the combine harvester is affected by vibration during operation and the generated error data in the process of collecting data which will cause the drawing results to be inaccurate.This study researched two factors that cause errors,then,the influence of vibration interference on the measurement signal was eliminated by filtering,vibration isolation,and designing a double-plates differential grain flow sensor.Three methods were taken to eliminate random errors,gross errors and systematic errors,including using the arithmetic average value to replace the true value,the 3σcriterion,and removing the filling time data and the delaying time data.Finally,the grain yield distribution map was obtained through Matlab and Excel.The results showed that the interference frequency above 50 Hz could be eliminated by filtering,but it was difficult to filter the low-frequency signal which was close to the grain impact frequency.The vibration amplitude was reduced to 14.29%by adding a vibration isolation plate,and the SNR was increased from−4.67 dB to 29.21 dB by combining low-pass filtering and damping vibration isolation.When the grain feeding rate was 2 kg/s,the natural vibration amplitude of the sensor after difference was about 0.02 V and evenly distributed around the zero voltage 0.2 V.The influence of positive and negative offset on the average value of grain impact signal could be ignored,and the signal-to-noise ratio was increased from 29.21 dB to 62.49 dB.The results of field experiments showed that the yield map drawn can clearly display the yield value of the harvest area,which is used to guide agricultural production.
文摘为减少联合收获机振动对谷物流量传感器监测结果的干扰,设计了一种基于声学黑洞(ABH,acoustic black hole)原理的谷物流量传感器龙门支架减振结构,通过有限元方法分析减振结构的振动特性,分析了二维声学黑洞比例系数ε、幂函数指数m和半径R对其减振性能的影响规律。结果表明,声学黑洞能够显著降低龙门支架的振动,ε、m和R对声学黑洞减振性能的影响均未表现出明显线性关系,当ε=0.001 2、m=2.5、R=15 mm时声学黑洞的减振效果最好。以振动速度平方和作为优化目标,建立了多项式回归代理模型,通过遗传算法对声学黑洞比例系数ε、幂函数指数m和半径R的取值进行了优化。相比于未添加声学黑洞的原始龙门支架和初始声学黑洞方案,优化后龙门支架的振动速度平方和分别降低68.92%和2%,表明优化方案具有更佳的减振性能。提出的基于声学黑洞的减振结构和优化设计方法为农业机械被动宽频减振研究提供了理论参考。
