Performance Improvement of Weighing System for a Weighing Sorter
Date Issued
2007
Date
2007
Author(s)
Chang, Chun-Chien
DOI
zh-TW
Abstract
Weighting sorter is one of the most popular machinery found in produce packers. Although load cell has been commercially applied in weight measurement for a long time, but in Taiwan it is still limited to be used in produce weighting sorter. Noise occurred by movement of mechanical elements and vibration of frame of the sorter greatly interference the weight measurement accuracy. In the thesis, by the use fast Fourier transform for the dynamic measurement signals of the load cell in a commercial sorter were identified as weighting signals distributed from 1 to 15Hz and the vibration noise mainly around 30Hz. Two methods were then implied to reduce the vibration noise in order to decrease the dynamic measurement error. First, a commercial software Multisim was used to simulate and design Twin-T band reject filters with cut-off frequency at 30Hz, filters were then realized through RC and Op-Amps circuits and were examined in dynamic measurements. The high quality Twin-T band reject filter with Q=0.65 gave the best results, the dynamic measurement error were lowered to ±5％. The second approach was to design a deconvolution filter using Simulink schema. Based on the dynamic response of the measurement system a deconvolution filter was simulated and materialize in the Simulink environment. The dynamic measurement signals were first digitally smoothed to eliminate high frequency noise and then processed with the deconvolution filter. With these process the dynamic measurement error were lowered to ±2 ％, that is fairly acceptable in the commercial measurement for a produce weighting sorter.
Subjects
重量分級機
雙T電橋帶拒濾波器
反摺積濾波器
動態量測誤差
weighing sorter
Twin-T band reject filter
deconvolution filter
dynamic measurement error
Type
thesis
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