Rajko Miodragovic

Effectiveness assessment of agricultural machinery based on fuzzy sets theory

Highlights? The concept of effectiveness - exact indicator of the quality of service of machine. ? New structure of max-min composition - outcomes as represent of If-Then rules. ? Evaluation of tractors - on the base of expertise judgment. The quality of service of agricultural machinery represents one of the basic factors for successful agricultural production. In this sense, there is a clear need for defining the exact indicator of the quality of these machines, according to which it could be possible to determine which machine is optimal for different working conditions. The concept of effectiveness represents one of synthesis indicators of the quality of service of the technical systems. In this paper the effectiveness is defined using the fuzzy set theory, and reliability, maintainability and functionality are used as influence indicators of the effectiveness. In that sense the model for assessing the effectiveness of tractor as a typical representative of agro machinery has been formed. The model is based on integration of linguistic description of the above mentioned influence indicators using fuzzy set theory and max-min composition. The model was tested on the example of three tractors of the same category, which are exploited in climatic and soil conditions in the wider Belgrade (Serbia) area. Even if the conditions in this experiment were approximately equal, the difference of the achieved effects was attained and very significant, compared to other operation parameters.

Water distribution uniformity of the traveling rain gun

An experimental method combined with a computer simulation technique, specified for optimizing the water distribution of a traveling rain gun system is presented in the paper. For given operational pressure and flat terrain, this method enables accurate evaluation of track overlapping and carriage velocity of the traveling rain gun that guarantee uniform water distribution at desired water deposit level. The evaluation criteria for water deposit quality have been formulated: minimum standard deviation, skewness factor as close to zero as possible and the highest possible flatness factor. It is verified that tested rain gun system achieves the uniform water distribution of 20.36 mm in lateral direction at track overlapping of 58%. The simple accurate formula specified for carriage velocity correction is also presented. Key words: Traveling rain gun, water deposition, track overlapping, carriage velocity, descriptive statistics.