Hydraulic power sharing on a hydrostatic transmission for a load–haul–dump for underground mines

Abstract

Hydrostatic transmissions can be used to drive mining machines when the size of the machine restricts the use of mechanical transmissions. However, hydrostatic transmissions lack a differential effect and when the machine navigates around corners there is an increase in the amount of vibration and discomfort to the operator. Thus, a method of introducing a differential effect is required. Three different approaches to generate a differential effect are presented: the application of cheater lines (hydraulic sharing between the inlets and outlets of the hydraulic pumps), power sharing (hydraulic sharing between the hydraulic displacement control), and a method of incorporating articulation angle corrections to provide the differential effect in the desired speed. The effectiveness of a proportional-integral (PI) controller is also considered for comparison. This work found that cheater lines performed better than power sharing and performed similar to methods where the wheel speeds are adjusted based on the articulation angle of the machine.