Dynamic performance analysis of a priority valve-controlled dual-function hydraulic steering system in load-haul-dump vehicles

This research presents an innovative hydraulic steering system for load-haul-dump (LHD) vehicles, featuring a priority valve-controlled dual-function design that aims to improve steerability while reducing power consumption. LHD vehicles are commonly used as front-end loaders in underground mining and construction operations. The proposed system integrates a priority valve and a hydro-pneumatic accumulator, enabling the simultaneous operation of both steering and cable reeling with a single drive. This integration significantly lowers the power requirements compared to operating these mechanisms separately. Additionally, the accumulator serves as a power assist unit (PAU) in emergency situations. The dynamic behaviour of the system under various operating conditions is examined using MATLAB/Simulink ® and validated through experimental testing. Results demonstrate that the priority function of the vehicle is preserved, even during cable reeling operations, and that the pressurized fluid stored in the accumulator can maintain vehicle steering for a limited period in the event of pump failure. By combining the steering hydraulics with the cable reeling drive, this design eliminates the necessity for an additional pump and couplers, thereby reducing the overall power demand of the machine by ∼46% compared to the conventional dual-pump configuration.