Admittance control for robotic loading: Underground field trials with an LHD

Abstract

In this paper we describe field trials of an admittance-based Autonomous Loading Controller (ALC) applied to a robotic Load-Haul-Dump (LHD) machine at an underground mine near Örebro, Sweden. The ALC was tuned and field tested by using a 14-tonne capacity Atlas Copco ST14 LHD mining machine in piles of fragmented rock, similar to those found in operational mines. Several relationships between the ALC parameters and our performance metrics were discovered through the described field tests. During these tests, the tuned ALC took 61% less time to load 39% more payload when compared to a manual operator. The results presented in this paper suggest that the ALC is more consistent than manual operators, and is also robust to uncertainties in the unstructured mine environment.