عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Using instrumented tractors to monitor and record spatial variations in performance parameters of tractor and implements during field operations, could improve productivity and the tractor efficiency. In the context of precision farming, this information can be used to map spatial variability of the parameters and to find the relations with changes in soil attributes (texture, moisture contents and degree of compactness) within a field. The objective of the research was to evaluate the tractor-implement performance parameters by equipping a Massey-Ferguson (MF-285) tractor with sensors to measure travel and engine speeds, wheel rpm and fuel consumption of the tractor, as well the draft of mounted implements. A Global Positioning System (GPS) receiver was also installed on the tractor. In order to display and collect data from the sensors, a data acquisition system was developed for the purpose. Appropriate methods were adopted to calibrate the sensors. A three-point hitch dynamometer which was developed previously at the Department of Farm Machinery, Isfahan University of Technology was calibrated in the field, employing RNAM method. Comparison of tractor wheel speeds with the fifth wheel revealed that the driven rear wheels and the non-driven front wheels had slip and skid respectively. The results showed that the fifth wheel and the non-driven front wheels are appropriate devices for a close estimation of the tractor travel speed. In a majority of the cases, the GPS accurately receiver indicated the tractor travel speed, however, due to the existence of obstacles on either side of the testing routes and the type of receiver employed, there was some jumping observed the recorded speed values. Therefore, its application in continuous travel speed measurement is somehow doubtful. The engine speed was recorded with an accuracy of 1 rpm using a combination of a toothed wheel and a magnetic proximity pickup. The installed Hall-effect fuel meter indicated the fuel consumption in different engine speeds with an accuracy of 0.1 L min-1. Dynamic (field) calibration of the three-point hitch dynamometer indicated that the RNAM method, for measuring draft of mounted implements, could only provide an estimation of the implement draft. The developed data acquisition system could collect data from the sensors with adequate precision. In addition to displaying the real-time information on its virtual display unit, the data were recorded as a text-file for further analysis. The instrumented tractor is ready for measuring and collecting spatial performance parameters of the tractor-implement ...