Multibody dynamic model and experimental verification of a closed-chain support mechanism for a rotary–percussive drilling rig

Abstract

Rotary–percussive drilling rigs operating in confined underground environments suffer from excessive vibrations in the closed-chain support mechanism, which significantly reduce borehole accuracy. This study presents the first high-fidelity three-dimensional multibody dynamic model of the support mechanism for a MK-Z49 rotary–percussive rig manufactured in Vietnam. The model employs a Lagrange-multiplier formulation to capture semi-closed kinematics and hydraulic actuation coupling, while realistic drilling forces and torques are reconstructed from full-scale experimental data using Fourier-series regression. The framework is rigorously validated on the MK-Z49 platform across nine distinct operating configurations, achieving excellent agreement between simulation and measurement (maximum deviation 5÷16%) in displacements, accelerations, and hydraulic pressures. Parametric sensitivity analysis identifies the boom-hoisting (XL2), boom-pushing (XL3), and guide-frame lifting (XL5) cylinders as the dominant contributors to vibration amplitude and borehole deviation. Feasible adjustments to standard piston diameters reduce maximum guide-point displacement by up to 48%, providing immediately actionable design guidelines for optimizing support-structure geometry and hydraulic systems. These results establish a validated, design-oriented platform that enhances drilling stability and accuracy in confined underground conditions.