Abstract:
Focusing on the intense vibration of high-frequency and high-power systems such as rock drills during the drilling process, this research investigates their drilling stability through nonlinear dynamics. A system dynamic model integrating rigid impact and rock contact theory is constructed, and the key influence of impact frequency on system dynamic characteristics is revealed using the Poincaré mapping method. As the impact frequency increases, the system gradually becomes unstable via period-doubling and saddle-node bifurcations, accompanied by a decline in energy utilization efficiency. Upon entering a chaotic state, although energy utilization efficiency shows a localized recovery, it is accompanied by more significant component wear. Due to the system's sensitivity to initial conditions, bistability is identified through forward and backward bifurcation analyses. A method based on Monte Carlo random sampling and on a trajectory classification is introduced to investigate the coexistence probability of each stable state. The bifurcation behaviors observed in simulations are verified through simulated rock drilling experiments, identifying the "one impact per period" mode as the optimal drilling pattern. This study provides a theoretical support and a decision-making guidance for the parameter optimization and for the stable operation of rock drills.