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Showing 2 results for Load Cell
A. Mokhtari, ُُs. Yousefi , M. Mosayebi ,
Volume 19, Issue 9 (9-2019)
Abstract
In the wind tunnels, the balance measurement instrument is used to measure six components of force and moment on an airplane model. The balance of measurement consists of two parts of the balance structure and electronic equipment. In this research, a mechanism with flexible hinges is designed to achieve the desired configuration of the balance structure. In the process of designing the geometric structure of this mechanism, an effective arrangement has been implemented for the six load cell - flexure columns. The advantages of flexible hinges in comparison to conventional hinges are the absence of friction, compactness and its linear behavior. The reaction effects of the components of force and moment on each six load cell - flexure columns created the coupling errors. One of the main sources of this kind of error is related to the structure of the balance mechanism. The reason for this type of error is the inadequacy of the axial flexibility to the lateral flexibility of the columns. The aim of this research is to optimize the design of the flexible mechanism in order to achieve the minimum coupling error of the structure. For this purpose, hinge design considerations and analytical equations of the flexible mechanism have been extracted. The design of the balance mechanism is optimized by creating a structure coupling error matrix. To validate the analytic equations and results, the problem is compared with the finite element analysis. The results indicated that the measurement errors decrease in the measurement of six components of force and moment of balance.
Volume 25, Issue 2 (2-2023)
Abstract
Yield monitoring is one of the parts of the precision agriculture that is best documented in practice and allows varying inputs according to the expected field outputs depending on spatially variable yield goals. The present study introduced a batch type Weighing System (WS) for the garlic bulbs yield monitoring. This WS includes a four-sector cylindrical container, rotary blades, a digital transmitter and array of two load cells for mass measurements. Electronic boards were used to control the WS and transfer the mass and georeferenced data. A LabVIEW interface was also developed to do the real-time signal processing. This WS was tested under laboratory and field conditions. Three factors including blades Rotation Speed (RS), Stop Time (ST) of blades, and Fraction of Stop Time (FST) were defined to find optimum load cell output. The lab tests were done to find the optimum value for these factors and the optimized WS was tested in the field condition. On the basis of WS outputs and actual weight of bulbs, the relative mean standard errors were determined as 1.94% in the lab and 4.26%, in the field. To demonstrate the spatial variability of crop-yield in the field, a yield map was plotted in ArcGIS using the data that were acquired by the WS and a GPS. The data recorded by the use of garlic yield monitoring system can be used in experimental studies to provide the basis for developing efficient nutrient management protocols and improve the management of garlic fields.
