Mechanical Model of Pick Cutter and Chaotic and Fractal Characteristics of Load Specctrum
|School||Heilongjiang Institute of Science and Technology|
|Course||Mechanical Design and Theory|
|Keywords||drum shearer pick-shaped cutter cutting resistance chaos fractal|
The process of pick-shaped cutter cutting coal is a major working process of coal mining machinery, which reflects the properties of the loads acted on the mechanism; determines the power needed for cutting coal and machine traction and the dynamics of the machine condition, the nonlinear of the force of pick-shaped cutter cutting coal, the uncertainty of coal mechanical behavior, and the inchoate theory system of pick-shaped cutter breaking coal; restricts the development of efficient mining machinery.The load spectrums of the cutter are tested by experimental device of pick-shaped cutter breaking coal, by the information of broken and damaged coal embedded in which, the pick-shaped cutter cutting coal mechanism and its characteristics and values of loads are recognized. By the orthogonal experimental research on the installation angle, transversal distance, chip thickness, feed rate and the load of pick-shaped cutter, the period of cutting coal and the natural characteristic of pick-shaped cutter geometry and force, and the interaction between them are determined. Based on the factors of coal fragmentation embedded in single cutter cutting resistance and the mechanism of cutter and coal, the cutting resistance spectrums of drum breaking coal are identified; the new method of determining drum instantaneous cutting resistance is presented based on single-cutter cutting resistance experiment spectrum, pick cutting law and working parameters; the experiment—theory model of drum cutting resistance is developed; three algorithms of cutting resistance model are given. Simulation results show that both characteristics and values of cutting resistance have good complex degree, reflecting the law of breaking coal, achieving the quantitative prediction calculation in engineering sense. By power spectrum method and Lyapunov index, the cutting resistance spectrum is studied from qualitative and quantitative two aspects, the results of which show cutting resistance spectrum has chaotic characteristics. The cutting resistance spectrum is analyzed with fractal theory; the box dimensions and related dimensions of cutting resistance spectrum of different installation angle cutter are got; and the fractal equivalent energy of cutting resistance spectrum is given. Giving mathematical description of performance Index of pick-shaped cutter breaking coal and realizing efficient personalization design of breaking institutions lay the groundwork for the development of high-end mining machinery.