Research of dynamics of movement of grain and forage harvesters by methods of mathematical and imitating modeling

The mathematical model of the grain and forage harvester movement is considered, the possibility of its algorithmization in the program complex is shown, and also the data confirming its adequacy are given. The mathematical model includes dynamic and kinematic equations of coupling angular and linear velocities with angular and spatial coordinates. The peculiarity of the model is the use of a set of coordinate systems, which allowed to take into account not only the mass and size features of the type of machines being studied, but also the nature of the interaction of the elastic wheel with the damped base. In the above model, the speed of the combine's movement is determined not by force change in the coordinate of the center of mass of the body, but is formed by modeling the process of interaction between the driving wheels and the support base. This approach provides a more adequate description of the process of curvilinear movement of the combine, allows modeling the car's starting, acceleration, braking, overcoming obstacles, skid and skid processes taking into account the characteristics of the tire and the coupling properties of the ground. The adopted approach provides sufficient accuracy of the model with a minimum set of factors and requirements for computation. Based on the developed mathematical model, a model is created in the simulink simulation environment of the MATLAB software package. Experimental and calculated data obtained as a result of imitation modeling are presented. A comparison of the operating forces and the spectral densities of acceleration in the main parts of the combine showed sufficient convergence of the results. The revealed inaccuracy is caused by the discrepancy between the numerical description of the supporting surface and the test road, the representation of the skeleton as an absolutely rigid body, the differences in the elastic-viscous properties of the tires. Conclusions are drawn and directions for further research providing for improving the operational properties of self-propelled combines by means of wheel suspension systems and working elements are determined.

self-propelled combine, dynamics of movement, mathematical model, simulation model, suspension