APPLICATION OF SENSITIVITY MEASURED PARAMETERS FOR MODELS EVALUTION.
Keywords:KEYWORDS, Tractive force, disc ploughing, loamy, sand, soil, modelling, sensitivity measurement, soil moisture.
Sensitivity measured parameters was used to evaluate a better tractive efficiency and tillage speeds. Predictive models for tractive force were developed using dimensional analysis. A disc ploughing tillage operations in a loamy sand soil, at tillage speeds of 1.94m/s, 2.22m/s and 2.5m/s were conducted, using trace tractor techniques. The independent and dependent variables involved in the models were measured. Developed mathematical models describing the tractors tyre-soil interactions parameters were evaluated using sensitivity of measured parameters. The wheel tractors tractive force models have sensitivity coefficients ranging from -0.01307 to 0.6705, -0.0058 to 0.7483 and -0.0024 to 0.8939 for ploughing , with all the independent variables at 1,94m/s,2.22m/s and 2.50m/s tillage speeds respectively. The results obtained showed that a 10% change of independent variable (U1) would cause dependent variable (N) a negligible change. The same negligible changes occur at 50% and 100% , even at the maximum change of 8.939 in ploughing operations. These indicate that the sensitivity of developed predicted models to changes in the constituent independent variables are negligible and insignificant. Thus, sensitivity coefficients of the tractive force models developed fit experimental data.