٢ TRACTOR FIELD PERFORMANCE PREDICTION VIA SIMULATION SOFTWARE M. Omid 1 , Y. Abaspour 2 and A.R. Keyhani 1 1 Assistant Professor, and 2 Ph.D. Student, Dept. of Agricultural Machinery, Faculty of Agriculture, University of Tehran, Iran. (Corresponding Author's e- mail: omid@ut.ac.ir) ABSTRACT: This paper presents a computer program that can be used for teaching tractors performance to undergraduate students of agricultural mechanization. In order to predict tractor field performance, tire performance, soil conditions and implement type are to be considered. As a result, a lot of empirical formulae as well as charts are involved. These sorts of problems are traditionally skill based rather than theory based. As a result educators have to illustrate problems keeping the hands-on approach in mind. One of the best ways to exemplify theory, to meet the above requirements, is the usage of simulation software and visualization techniques. Simulation software help students to better understand the performance aspects of tractors in the field from the pure science aspects of the subject matter. This software would also help manufacturers, designers and tractor operators to improve tractor performance by analyzing the many factors involved. The simulation software program provides a quick and relatively inexpensive method to evaluate tractor performance. The interface was designed with Visual Basic 6.0 and can be used to predict the performance as well the tractor's specific volumetric fuel consumption for agricultural soils using either bias-ply or radial-ply tractor tires. Other features include provision for changing model parameters, adding new model, saving data using Excel's spreadsheet and printing the results. Relative magnitudes of the many factors affecting field performance of a tractor can, therefore, be determined using computer modeling or simulation without conducting expensive field tests. KEYWORDS: tractor, prediction, performance, mechanization, teaching/learning methods, modeling, interface design, software, visual basic