Multi-criteria justification of unit coupling ability of moving power units using the example of the drawbar category 3

BACKGROUND: This paper covers the issues of evaluating the unit coupling ability of mobile power units — the drawbar category 3 tractors, in a multi-criteria formulation. 9 main functional and operational characteristics of tractors being coupled as part of a machine tractor unit were adopted as evaluation criteria. The following criteria limitations were considered in the optimization calculations of unit coupling: “Coupling capacity”, “Tractor base”, “Tractor load capacity”, “Maximum power of the power take-off shaft”, “Limitations on handling of the tractor as part of the machine tractor unit”, “Hourly capacity”, “Traction force on the drawbar”, “Technical tractor readiness”, “mobile power unit coupling ability coefficient”. The use of multi–criteria optimization algorithms and software tools makes possible having a wide range of applications: at all stages of the full life cycle of mobile power unit — development, production, operation, disposal. AIM: Conducting the optimization analysis for evaluating the unit coupling ability of the drawbar category 3 wheeled tractors, taking into account numerous quality criteria and functional limitations, which make it possible to expand the range of machine used as part of the machine tractor unit. METHODS: For conducting the optimization analysis in the studied parameter space, variation ranges of variable parameters were formed according to the problem statement and the preferences of the decision maker, criterial and functional constraints were made for further determination of the admissible and Pareto set of solutions. RESULTS: As a result of the analytical and optimization calculations, 3 Pareto-optimal variants of mobile power unit coupling ability and 12 acceptable variants satisfying the criteria and functional constraints were obtained. According to the decision maker, the points with the following values of the machine tractor unit coupling ability criteria were chosen as the most preferable among the Pareto points obtained for the drawbar category 3 wheeled mobile power units: coupling capacity — 2.5 tons; base length — 2.45 m; load capacity — 3.5 tons; maximum power of the power take-off shaft — 56 hp.; handling of the machine tractor unit — not less than 0.78 tons; hourly capacity of the machine tractor unit — 2.5 ha / hour; traction force on the drawbar — 35 kN; the coefficient of technical readiness — 0.86; the coefficient of unit coupling ability of the tractor — 0.9. CONCLUSION: The conducted analysis of the unit coupling ability of wheeled tractors made it possible to identify the most preferable options based on the given constraints. The results suggest a high level of significance for the criteria under consideration.