Spatial factors affecting the loading efficiency of excavators

•The spatial factors affecting the loading operation of excavation work were identified.•The loading operation was broken down into several movements to collect data.•The relationship between loading efficiency and spatial factors of excavators was analyzed.•Two hypotheses on the loading efficiency were examined based on the truck loading cycle time.

Excavators are typical machinery in the construction industry, and have advantages when applied in various tasks. Among various tasks of excavators, loading a dump truck is a very important task that could be automated. However, most of the previous studies are focused on the excavation/digging operation, and the studies on the loading efficiency are limited. Therefore, the spatial factors affecting loading operation were identified and investigated with regard to the different types of the movements of the machine in this study. To observe changes in the loading time according to the affecting factors, two main hypotheses were examined as follows: 1) loading time changes according to the height difference and distance between the excavator and dump truck; and 2) loading time changes by the rotation angle. In order to verify the hypotheses, the movements of three excavators were studied under the different conditions of the spatial factors. We believe that the automation of loading operation for excavators can benefit from the results of hypothesis validation, and from the analysis of the detailed loading operation in relation to the categorized movement and the patterns of loading operation.