Applicability of Automated Digging Algorithm on Sloping Ground for Hydraulic Excavators

In the digging operation of hydraulic excavators, the operator engages two levers simultaneously to control three hydraulic cylinders. High-level skills are required for high-efficiency operation. Hydraulic excavators require some support technologies for improving their operation efficiency, saving fuel, and providing a support function to novice operators. We propose an automated digging algorithm to improve digging performance. The algorithm switches between two digging modes—raking and lift-up—to avoid cylinder stall and reduce the energy loss of hydraulic energy through excessive cylinder force. The digging mode is selected based on a preset cylinder force threshold. Switching these modes allows us to control the value of the cylinder force to remain in the vicinity of the threshold force. We performed some parameter studies using a simulation model based on terramechanics and an excavator’s front linkage dynamics. This automated digging algorithm is performed on flat ground, but here we focus on digging on a slope. We slightly modified the automated digging algorithm for flat ground to apply it to the slope. The simulation results show that this automated digging algorithm is also applicable to slopes.